Amazon guesses what your inventory cost you. The guess runs low.
Since March 2025, undocumented lost or damaged units get valued at Amazon’s own cost estimate rather than at what you paid. Costback keeps your real, invoiced cost per SKU on file, so the number you dispute with is documented, not guessed.
Illustrative figures. Costback reads the cost you document; Amazon decides every claim.
Undocumented units get valued at Amazon’s estimate.
When a unit is lost or damaged and you have no sourcing cost on file, the reimbursement is calculated from Amazon’s own figure. Costback keeps an effective-dated cost per SKU with the invoice attached, so the higher number is the documented one.
Three things that stay true, on every plan.
We defend your sourcing cost
Amazon's 2025 cost-basis rule values undocumented units at its own estimate rather than at what you paid. Costback keeps an effective-dated cost per SKU with the invoice behind it.
You keep 100%, always
Flat monthly fee, not a cut of your recovery. If Amazon later reverses a reimbursement, you don't owe a commission on money you no longer have, because we never took one.
We never log into your Amazon account
No Seller Central credentials, no OAuth, no API keys. You export the report; Costback reads the file you upload.
You upload. You review. You file.
Costback never logs into Seller Central and never submits anything for you. It reads the reports you export and hands you a case-ready package.
Upload your report
Export Reimbursements, Inventory Ledger or Returns from Seller Central and drop the CSV in. Nothing else is read.
See claim-eligible discrepancies
Costback reconciles the file line by line and lists the candidates: lost, damaged, fee overcharges, unreturned returns — each with its valuation basis and window.
File them yourself
Review every item, copy the case-ready package, and open the case in Seller Central under your own account. Amazon decides all claims.
The honest FAQ
Including the questions that don’t flatter us.
Does filing get me suspended?
Filing legitimate, documented cases is a normal part of running an FBA account. What harms Account Health is volume without substance: duplicate cases, claims for units already reimbursed, or inflated values you can't evidence. Costback flags duplicates and shows the evidence behind every figure, and it deliberately makes you review each item before you file — that review step is the protection.
Why don't you file for me?
Filing requires access to your Seller Central account. We don't take that access, so we can't file, and we won't ask for it. You paste the package into your own case. It also means nothing is submitted in your name without you reading it first.
Doesn't Amazon already reimburse lost inventory automatically now?
For some items, yes. Amazon started proactively reimbursing units lost in its warehouses in late 2024. What that automation doesn't fix is the amount: if you don't have a documented sourcing cost on file, those automatic reimbursements are still valued at Amazon's own estimate, not what you actually paid. Costback's job isn't getting a claim filed, it's making sure the number behind it is yours.
Is this a percentage-of-recovery service?
No. Costback is a flat monthly subscription. Commission services typically take around 25% of whatever Amazon pays out, and some keep that commission even after Amazon reverses the reimbursement, so you can end up paying a fee on money you no longer have. With Costback, the reimbursement is yours in full, every time.
What data do you read?
Only the reports you upload — Reimbursements, Inventory Ledger, Returns, Fee Preview, and the invoices you attach to SKUs. We do not process buyer names, addresses or order-level customer data; if a report you upload contains it, we refuse the file and tell you which report to export instead.
How much will I get back?
We can't say, and anyone who does is guessing. Costback shows what your own reports suggest is outstanding and what the valuation basis would be. Amazon decides every claim, and some are denied.
What if my reports show nothing?
Then you file nothing and you'll know your account is clean — which is worth knowing. You can cancel the same day; billing is monthly with no lock-in.
Start with your own Reimbursements report.
The estimate is free and needs no account. We only read that one report — never buyer data.