Duplicate supplier payments: recover the money and fix the control that allowed it

A duplicate supplier payment can happen when the same invoice is entered twice, a failed-looking transfer is resent, or a manual payment is made outside the normal accounts-payable run. Recovery is usually easier when the supplier is genuine, but finance should still treat the incident as a control failure and verify the refund destination carefully.

Confirm that two bank payments really relate to the same liability

Compare supplier, invoice number, purchase order, amount, bank reference and payment date. Two identical amounts can be legitimate if the supplier issued two equal invoices, while one invoice can also be split into several valid payments.

Do not ask the supplier for money back until accounts payable proves the duplicate. Record the incident number and identify which payment was authorised first and which created the overpayment.

Contact the bank quickly if the duplicate was just released

If finance notices the error immediately, ask the bank whether the payment is still cancellable or whether a recovery request can be started. Faster Payments cannot simply be cancelled once sent, so the bank may only be able to request return.

Keep the recovery case reference. Do not send a third transaction to "correct" the balance without understanding the first two payments because that can compound the error.

Ask the supplier to return the overpayment through a verified route

For a genuine supplier, send the payment evidence and request repayment or agree that the amount will be held as a supplier credit. Get written confirmation of which treatment will apply.

If the supplier returns cash, verify that the refund comes to the company's own account. Never provide a different employee or director account because someone says it will be faster. The overpayment belongs to the company.

Verify any refund-account change independently

A duplicate-payment conversation can itself become a fraud opportunity. An attacker who compromises supplier email can offer to return the money but request "confirmation" of new bank details or send a fake refund link.

Use the company's bank details already on file with the real supplier and verify any communication through a trusted channel. The finance team should not disclose more account information than the supplier needs to make the return.

Find whether the cause was invoice duplication, bank retry or manual bypass

Common causes include duplicate invoice entry, poor invoice-number controls, two payment batches containing the same item, payment outside ERP, or an employee resending a transfer after a banking error message.

Fix the specific cause. ERP duplicate detection will not solve a payment resent manually after an outage, and a bank approval limit will not solve the same invoice being entered twice under slightly different invoice numbers.

Keep the supplier account open until cash or credit is resolved

Record the overpayment as a supplier receivable or credit according to the accounting system. If the supplier applies it against future invoices, clear the credit only as those invoices become due.

Track aged supplier credits just like aged customer debts. A £20,000 overpayment left as a dormant credit for a year is still company cash trapped outside the bank and deserves active recovery.

Use a duplicate-detection control before each payment run. Match supplier, invoice number, amount and purchase order against paid history, and flag near matches where punctuation or prefixes differ. Fraud or error can enter the same invoice as INV-1023 and 1023, defeating an exact-text duplicate check.

Worked example: a £35,000 supplier invoice is paid in Friday's batch and then manually resent Monday after somebody misreads the bank status. Finance should immediately confirm both payments, contact the bank and supplier, and freeze further manual payment on that invoice until the overpayment is resolved.

Review aged supplier debit balances monthly. Duplicate payments can remain hidden as unexplained credits for months when accounts payable focuses only on amounts the company owes. A supplier debit is company money outside the bank and should have an owner and recovery date.

Include duplicate-payment risk in bank-outage procedures. A common scenario is that an employee sees a timeout after approving a transfer, assumes the payment failed and resends it through another channel. The contingency plan should require status confirmation before replacement and a senior sign-off for any second material payment.

Measure annual duplicate-payment value and recovery time. Even where 100 percent is eventually recovered, money can remain outside the business for weeks. That hidden working-capital cost helps justify investment in better AP controls, supplier-master governance and automated duplicate detection.