Quick answer. An FBA prep center can label, bag, box and ship your inventory to Amazon, but Amazon treats every unit as yours. If the prep partner mislabels units, ships the wrong condition, misdeclares cartons, or mixes your stock with someone else’s, the refusals, fees, reimbursement denials, condition complaints and authenticity complaints land on your account. Amazon’s FBA restrictions page lists account deactivation among the possible results of prep failures. To use a prep service safely, vet the business behind it, require a written receiving and labeling procedure, keep chain of custody records and photos for every shipment, and reconcile every shipment against what Amazon received.
A prep center receives supplier freight, labels and packs units to Amazon’s standards, and ships cartons to fulfillment centers. When it goes wrong, the seller usually finds out weeks later from a receiving discrepancy, a stack of “used sold as new” returns, or an Account Health notice naming an ASIN they thought was clean.
Amazon does not see your prep center. It sees your shipment, your FNSKU, your condition setting and your customer complaints. This is educational information, not legal advice.
Why Amazon holds you responsible for your prep partner
When you create a shipment in Seller Central, you declare what is in each box, including the SKU, barcode, FNSKU, condition, quantity, packing type and box weights and dimensions. Amazon’s shipping and routing requirements list those details and say the shipping plan must match the shipment you sent. A prep center may pack the box, but the declaration is yours.
Amazon’s reimbursement policy follows the same logic. To be eligible, the item must comply with FBA product restrictions and inventory requirements, and you must have sent the exact items and quantities stated in your shipping plan.
What Amazon says can happen when prep fails
Amazon’s FBA product restrictions page states that failing prep, safety and product restriction requirements may result in refusal, disposal or return of inventory, blocking of future shipments, charges for preparation or noncompliance, deactivation of your selling account, or fines. The packaging page adds that non-compliant, unsafe packaging may be refused or disposed of at your expense and will not be eligible for reimbursement. The shipping and routing page lists inbound defect fees. The shipment claims page says sellers who generate many shipping problems may face additional investigation and monitoring that could affect Prime eligibility or delay reimbursements. None of those outcomes depend on who applied the label.
What Amazon requires before inventory reaches a fulfillment center
You need to know these requirements well enough to audit your prep partner. Amazon updates its packaging, barcode and shipping and routing pages, so check the current versions before approving a new product type.
Barcodes and FNSKU labels
Amazon’s FBA barcode requirements page says every item sent to a fulfillment center needs a barcode, either a manufacturer barcode such as a UPC, EAN, JAN or ISBN, or an Amazon barcode, which is an FNSKU label that starts with an X. A notice on the page says barcode requirements changed as of March 31, 2026. Brand owners can continue to use manufacturer barcodes without stickers, while resellers must use Amazon barcodes even if the product has a manufacturer barcode. Resellers should get written confirmation that the prep partner labels every unit.
These packaging rules matter most for label work.
- Any FNSKU you use on a unit must be unique and correspond to one unique product. Each size, color or other assortment type needs its own FNSKU.
- Items offered in different conditions, such as used like new and used good, must have a unique FNSKU.
- Each unit needs an exterior scannable barcode or label with the corresponding human-readable numbers, easy to access, and not placed on a corner or curve that would prevent scanning.
- Any other scannable barcodes on the outside of shipping boxes must be removed, covered with opaque tape, or crossed out with a black felt-tip marker so the wrong code is not scanned at receiving.
For how barcode choices affect an account, read our guide to knowing your barcodes and protecting your account.
Packaging and prep by product type
A unit that falls under several categories must be prepped for all of them. These are the rules prep centers most often miss.
- Sets must be labeled, for example “Sold as set,” and sealed so they cannot be separated.
- Boxed units must be six-sided. Products over 10 lb or sharp products need a double-wall corrugated box.
- Poly bags with a 5-inch opening or larger, measured flat, must carry a suffocation warning.
- Case packs must hold matching SKU and condition, packaged together by the manufacturer, in equal quantities, up to Amazon’s stated limit of 150 units per case.
- Expiration dates must read MM-DD-YYYY or MM-YYYY, on units and on the outer box in 36-point or larger font.
- No extras. Remove pre-priced labels, price tags and theft-prevention devices.
Cartons, box labels and box content
Each box needs its own FBA Box ID label printed from your Shipping Queue, and each pallet needs four FBA Pallet ID labels. Boxes must not exceed 36 by 25 by 25 inches or 50 lb unless a single oversize item requires more. Boxes over 50 lb need Team Lift or Heavy Package labels, and no box may weigh more than 65 lb. Jewelry and watch boxes must not exceed 40 lb. Packing peanuts, foam strips, crinkle wrap and shredded paper are not allowed.
Accurate box content information helps prevent blocked shipments and a manual processing fee, so your prep partner should record what went in each carton.
Related guides. How to Respond to a One-Star Amazon Review Without Breaking Amazon Policy and Amazon FBM vs FBA.
For a closely related case, read Amazon Seller Challenge.
What goes wrong when a prep partner makes mistakes
Prep failures fall into a few patterns. The pattern tells you what evidence to pull and which control to install. Use the tabs to compare them.
Receiving defects and inventory discrepancies
A receiving discrepancy is the most common early warning. Suppose a hypothetical seller sends 480 units in 8 cartons of 60, and the Contents tab shows 420 received. The prep center’s intake log shows the supplier delivered only 7 full cartons, and the prep center built the shipment at 480 by copying the supplier’s packing list. Amazon did not lose 60 units, so a reimbursement claim would be inaccurate. The right outcome is a supplier credit, a written correction from the prep center, and a rule to count against the packing list before any shipment is built.
Mislabeled units and condition errors
Mislabeling reaches buyers directly. Open-box supplier units labeled New produce condition complaints. Amazon’s condition guidelines treat items that are damaged, missing necessary parts, in need of repair, or not made by the original manufacturer as unacceptable, and those standards apply to whatever the prep center ships under your listing.
Commingling at the prep center
Physical commingling happens when a facility stores identical products from several clients together and pulls whichever units are nearest. If another client sourced badly, your listing can receive their units. A prep center that cannot show how it separates client inventory by location and record is a risk however clean your own sourcing is.
How prep problems become account problems
Prep errors usually surface first as operational signals (discrepancies, refused units, inbound defect fees), then as customer signals (returns and complaints about used, damaged, wrong or not genuine items), and then as enforcement, such as ASIN action, an invoice request, or an account review.
Watch condition complaints closely. “Not as described” and “not genuine” sit close together, and a cluster of “used sold as new” or “damaged” complaints on one ASIN can draw authenticity scrutiny. Our explainer on inauthentic versus counterfeit complaints covers how the two differ.
For how ordinary FBA errors compound, see Amazon FBA mistakes and their bitter consequences and our overview of facts you need to know about Fulfillment by Amazon.
How to vet a prep center before you send a single unit
Vetting removes most of the risk. Treat a prep partner like any supplier that can affect your account, and ask for evidence, not assurances.
Confirm the business is real and in good standing
Get the prep center’s exact legal entity name and state of formation, then check it in that state’s business registry. The National Association of Secretaries of State maintains a corporate registration page linking to each state’s business registration pages and corporate name databases. Look for an active status and a registered name that matches the contract and invoices. If they do not match, stop and ask.
Insurance and references
Ask for a current certificate of insurance and confirm it covers inventory in the prep center’s care against loss, theft and damage, and to what limit. Amazon’s reimbursement policy covers only inventory lost or damaged at facilities or by carriers operated by or for Amazon, so the prep center’s insurance and contract are your recovery path for that stage. Then call references who ship similar products. Ask how often their shipments show discrepancies and how the prep center reports intake shortages.
A written procedure and chain of custody records
A prep center without a written receiving and labeling procedure is improvising. The procedure should cover counting against the packing list, photographing condition, reporting discrepancies before work begins, storing each client’s inventory in separate recorded locations, labeling from your own label file, and recording carton contents. Make delivery of date-stamped intake logs, photos, location records and carton lists a contract term.
The records to keep for every shipment
When a claim is filed, Amazon’s shipment claims page asks for the Amazon shipment ID from your Shipping Queue, proof of inventory ownership such as a supplier invoice showing the date of purchase, product names matching the lost or damaged items and quantity, and proof of delivery. For less-than-truckload and full-truckload freight, proof of delivery is a document showing the number of boxes and total weight at carrier pickup, stamped by Amazon to confirm receipt. For small parcel, Amazon needs active tracking IDs. If you did not use an Amazon partnered carrier and did not enter tracking when creating the shipment, you must enter it before you can be reimbursed.
Proving what your prep partner did takes more. Keep these records in one folder per shipment ID.
| Record | Who produces it | What it proves |
|---|---|---|
| Supplier invoice and packing list | Supplier | What you bought, when, from whom, and in what quantity |
| Inbound tracking to the prep center | Supplier or carrier | That the goods were delivered to the facility and when |
| Intake count and discrepancy report | Prep center | What arrived, and any shortage before Amazon was involved |
| Intake condition photos | Prep center | Condition of cartons and sample units on arrival |
| Storage location record | Prep center | That your inventory was kept apart from other clients |
| Label file and labeled unit photos | You and prep center | Which FNSKU went on which product and condition |
| Carton contents, weights and dimensions | Prep center | That each box matched what you declared in the shipping plan |
| Outbound tracking or stamped proof of delivery | Carrier | That the cartons reached Amazon |
| Contents tab export and reconciliation note | You | What Amazon received against what was sent, and how gaps were resolved |
Never alter an invoice, packing list or photo to make a shipment look cleaner than it was. Amazon’s reimbursement policy says it may decline sourcing cost submissions where documentation is forged, tampered with or illegible, and altered documents in any account review do far more damage than the original problem. If you cannot obtain a genuine document, say so plainly and present the records you have.
How to verify what happened, step by step
When something looks wrong, verify before you act. Most bad outcomes come from acting on an assumption, such as filing a claim for units that never shipped, blaming a buyer for a real condition problem, or blaming the prep center for a supplier issue. Start at the shipment’s Contents tab and work back through the prep center’s records to the supplier invoice. For complaints, match the affected ASINs and order dates to the inbound batch they came from.
| Question | Where to check | What to look for |
|---|---|---|
| Did Amazon receive what I sent? | Shipping Queue, shipment Summary, Contents tab | Shipped versus received by SKU, and the investigation eligibility status |
| Have I already been paid for missing units? | Reimbursements report in Seller Central | Any reimbursement tied to the shipment or SKU |
| Is my sourcing cost on file? | Manage Your Sourcing Cost page in the Inventory Defect and Reimbursement portal | Your submitted cost or Amazon’s estimate for each item |
| Did the prep center receive what the supplier sent? | Prep center intake report and supplier packing list | Count differences and damage noted on arrival |
| Were the boxes packed as declared? | Prep center carton contents list and sealed carton photos | Units per box, weights, dimensions, Box ID labels |
| Did the cartons reach Amazon? | Carrier tracking, or bill of lading and stamped proof of delivery | Delivered status, box count and weight at pickup |
| Is my prep partner a real, active business? | State business registry, reached through nass.org | Active status, matching legal name, formation date |
| Is the barcode rule for my products current? | FBA barcode requirements in Seller Central Help | Whether you must use Amazon barcodes as a reseller |
| Does the unit meet the listed condition? | Condition guidelines in Seller Central Help | The definition of New versus used grades and unacceptable conditions |
Shipment claims and the filing window
If your reconciliation shows units were lost or damaged after the prep center handed them to the carrier, Amazon’s shipment to Amazon claims page sets the rules. You can file once a shipment shows as eligible for investigation. Amazon says you must submit the claim no later than nine months after the verified date of delivery to a fulfillment center or a third-party facility operated on Amazon’s behalf, and claims outside that window are not eligible. You may file only one claim per shipment, and additional claims for the same shipment will be declined. Reconcile fully, then file once.
For pre-order losses such as shipment to Amazon claims, Amazon reimburses your sourcing cost, excluding shipping, handling and duties, or its own estimate if you have not provided one. Your account must be in normal status when you file and while the claim is reviewed. If you have a backlog of discrepancies, our Amazon inventory reconciliation service handles the unit-by-unit work.
A prep mistake now sitting on your account?
Send us the notice or the shipment records and we will tell you plainly where the gap is.
What to do if your prep partner caused a violation
It is your account, so it is your responsibility. “My prep center did it” is not a plan of action. A credible response gives a clear root cause, proof of corrections already made, and controls that stop recurrence, and it explains why your process let the prep error through.
Diagnose what the prep partner did
Establish the specific conduct, whether a miscount, a labeling error, condition units shipped as New, your stock mixed with another client’s, or substituted goods. Reconstruct it from what you sent in, what the facility did, and what reached buyers. Ask the prep center in writing for its intake logs, location records and photos for the affected batch.
Prove your own sourcing was genuine
If the complaint touches condition or authenticity, the case rests on your genuine supplier invoices for the affected ASINs. If your sourcing was not genuine, the prep center is not the root cause, and blaming it will fail.
Corrective actions and preventive controls
Corrective actions are things you have already done, with dated proof, such as removing suspect inventory, refunding affected buyers, pausing or leaving the prep center, and getting its written incident report. Preventive controls stop recurrence, each with a named owner and start date. Examples are intake counts and photos before any shipment is built, a second-person label check, separated client storage written into the contract, and condition inspection of every batch before it is labeled New.
Write the plan of action
A hypothetical example. Root cause. A supplier batch received on a stated date included open-box units, and the prep center labeled the whole batch New because the seller’s work order did not require an intake inspection. Corrective actions. Remaining units from the batch removed on a stated date, affected buyers refunded, shipments from that facility paused. Preventive controls. Intake condition inspection with photos of every batch, owned by the operations manager from a stated date, and a contract term requiring the prep center to report open-box or damaged units before labeling. The plan blames neither buyers nor the prep center and names the gap in the seller’s own process. If your account has already been deactivated, our Amazon suspension team can review the notice and the records with you.
Common mistakes sellers make with prep services
Choosing on price and never looking at the inventory
The cheapest rate often comes from a facility that skips intake counts, photos and second checks, the controls that protect you. Sellers who never read intake reports learn about problems only from Amazon or buyers.
Filing claims before reconciling
Amazon’s reimbursement policy warns that insufficiently researched or premature requests, or many requests in a short time, can lead to delayed support, monitoring, investigation and account action. A claim for units the prep center never shipped is that kind of request.
Ignoring early condition complaints and keeping records only at the prep center
Two or three “used sold as new” returns on an ASIN are a signal, not noise. Match them to the batch that produced them. If the prep center closes or stops responding, its records go with it, so keep your own copies by shipment ID. Our article on Amazon inventory management mistakes covers related habits.
A repeatable routine that keeps prep problems small
Every unit should be traceable from your supplier invoice to the Amazon Contents tab, and every gap explained before Amazon has to ask.
- Every shipment. Send a complete work order, read the intake report before the shipment is built, confirm carton contents against the plan, file tracking and proof of delivery, and reconcile the Contents tab when receiving closes.
- Every month. Review returns and complaints by ASIN for condition or authenticity wording, match clusters to their inbound batch, and check open discrepancies against your Reimbursements report so none drift toward Amazon’s claim window.
- Every quarter. Re-check the prep partner in the state registry and its insurance, re-read Amazon’s packaging, barcode and shipping pages for changes, and walk one completed shipment from invoice to Contents tab using only your own records.
Frequently Asked Questions
Am I responsible if my FBA prep center makes a mistake?
Yes. You declare the shipment contents to Amazon and the inventory sells under your account, so refusals, fees, complaints and enforcement land on you. Your recovery against the prep center runs through your contract and its insurance.
Do resellers have to put FNSKU labels on every unit?
Amazon’s FBA barcode requirements page states that as of March 31, 2026, resellers are required to use Amazon barcodes even if the product has a manufacturer barcode. Brand owners can continue to use manufacturer barcodes without stickers.
Can a prep center mistake get my Amazon account suspended?
It can. Amazon’s FBA product restrictions page lists account deactivation among the possible results of prep failures, and prep-caused condition or authenticity complaints can also lead to account action.
Will Amazon reimburse units lost at my prep center?
No. Amazon’s reimbursement policy covers items lost or damaged at a facility or by a carrier operated by or on behalf of Amazon. Losses at your prep center fall to your agreement with that facility and its insurance.
How long do I have to file a claim for units missing from a shipment?
Amazon says shipment to Amazon claims must be submitted no later than nine months after the verified date of delivery to a fulfillment center, and you may file only one claim per shipment.
How do I check whether a prep center is a legitimate business?
Search its exact legal name in the business registry of its state of formation, reachable through the National Association of Secretaries of State, and confirm an active status and a name matching the contract.
What should a plan of action say if my prep center caused the problem?
It should state the specific root cause, including the gap in your own process that let the prep error through, the corrective actions you have already taken with proof, and preventive controls with a named owner and start date. Blaming the prep center alone will not satisfy Amazon.
Get Help With Prep Center Problems and FBA Discrepancies
If a prep partner’s mistake has turned into receiving discrepancies, declined claims, condition complaints or an Amazon notice, we can review your shipment records, rebuild the reconciliation and help you prepare an accurate response. You can submit your case for review or book a consultation to review your prep setup before something goes wrong.
This article is educational information, not legal advice, and does not guarantee any outcome with Amazon. Amazon’s requirements, fees and claim windows change, so confirm the current versions in Seller Central Help before you act.
Our Amazon inventory reconciliation team can take the case from here. You can also see all our marketplace suspension services.
Sources
- Amazon Seller Central Help: FBA product restrictions
- Amazon Seller Central Help: Product packaging requirements
- Amazon Seller Central Help: FBA barcode requirements
- Amazon Seller Central Help: Shipping and routing requirements
- Amazon Seller Central Help: FBA inventory reimbursement policy
- Amazon Seller Central Help: FBA inventory reimbursement policy, Shipment to Amazon claims
- Amazon Seller Central Help: Condition guidelines
- National Association of Secretaries of State: Corporate registration
