If you overpaid a vendor or paid the same bill twice, act fast: confirm the error against your bank record and AP ledger, ask your bank whether the payment can still be reversed, and put a written refund request to the vendor the same day. Recovery is straightforward when the error is fresh. It gets harder every week the money sits on the vendor’s side.
Confirm the Overpayment Before You Do Anything Else
Pull the bank disbursement record, match it against your AP ledger, and compare both to the original invoice. You need three specific facts: the exact overpayment amount, the date the payment cleared, and the method used (ACH, wire, or check). A duplicate payment usually jumps out once the records are side by side. An overpayment on a single correct invoice takes more digging, because the line items can look right at a glance while the total is off.
Write up an internal incident report while the details are fresh. Include the invoice numbers, payment reference codes, the correct amount owed, and the amount actually paid. If recovery drags on, or if you eventually have to write the balance off, that documentation is what supports the claim.
Try to Pull the Payment Back Through Your Bank
Before you contact the vendor, find out whether your bank can still stop or reverse the payment. This is the fastest possible outcome because it doesn’t depend on the vendor’s cooperation.
For an ACH transfer, Nacha rules permit reversals for duplicate payments, payments sent to the wrong account, and incorrect payment amounts.1Nacha. End User Briefing – Reversals The reversal has to be initiated within five business days of the original settlement date, so call your bank the same day you spot the error. A successful reversal pulls the funds back without touching the vendor at all.
For a paper check, ask the bank to place a stop payment if the check hasn’t cleared. Once it’s been cashed, that option is gone and you’re pursuing the vendor directly.
Contact the Vendor the Same Day
Don’t wait for your internal review to be perfect before reaching out. Call the vendor’s accounts receivable department and follow the call with a written summary the same day. Early notice establishes your claim on the record, and most vendors with a functioning AR department will confirm the overpayment quickly once they pull their own file.
Then send a formal written request on company letterhead. Include copies of the original invoice, both payment confirmations if it was a duplicate, and your internal documentation of the error. Specify a refund deadline. Thirty days is standard for commercial relationships. If the vendor doesn’t respond, follow up in writing and escalate to their management.
Refund or Credit Memo
Recovery takes one of two forms: the vendor sends a refund, or the vendor issues a credit memo you can apply against future invoices. Push for a direct refund when the overpayment is large relative to your usual purchase volume with that vendor, or when you’re not confident you’ll do enough future business to consume the credit within a few months. A credit that lingers for a year creates its own problems, including the escheatment risk covered below. For a small overpayment with a vendor you order from regularly, a credit memo applied to the next invoice is often the fastest resolution.
When the Vendor Won’t Return the Money
Most overpayment disputes resolve without lawyers. When one doesn’t, the legal claim is unjust enrichment: the vendor received money they weren’t entitled to, you’re worse off by that amount, and it would be unfair to let them keep it. Courts across the country recognize the claim, and the elements are consistent: the vendor was enriched, the enrichment came at your expense, and allowing them to keep the funds would be unjust. A clearly documented duplicate payment leaves the vendor with essentially no defense.
The statute of limitations varies by state, typically running two to six years from the date of the overpayment. That sounds generous, but practical recovery gets harder much faster than the legal deadline suggests. Contacts change, records get archived, and the vendor may have restructured or closed. Treat any overpayment older than 90 days as urgent.
For amounts too small to justify a lawyer, small claims court is usually the most practical route. Jurisdictional limits range from $2,500 to $25,000 depending on the state. Filing fees are low, and the process is built for self-representation. Filing the claim, or credibly threatening to, is often enough on its own.
For larger amounts, a demand letter from an attorney typically runs a few hundred dollars and signals you’re prepared to litigate. If the balance is substantial and the vendor is stonewalling, commercial litigation may be warranted, though the analysis should weigh attorney fees, time to resolution, and the likelihood of collecting on a judgment.
Fix Your Books
An overpayment distorts your ledger whether or not you’ve gotten the money back yet. When the excess payment goes out, cash drops by more than it should, and the vendor’s sub-ledger in accounts payable shows a negative balance, meaning the vendor now owes you.
Reclassify the overpaid amount out of accounts payable into a receivable account, typically labeled “Other Receivables” or “Vendor Receivables.” The entry debits the new receivable and credits accounts payable, which clears the negative balance and accurately reflects that you have a claim against the vendor.
When the refund arrives, debit cash and credit the receivable. If the vendor issues a credit memo instead, apply it against the next invoice: debit accounts payable for the new invoice amount, credit the receivable for the portion offset by the memo, and pay any remainder in cash. After posting the correction, reconcile your AP ledger against the vendor’s AR statement so both sides show matching balances. That last step keeps the error from resurfacing as a billing dispute months later.
If You Genuinely Can’t Recover the Money
When an overpayment becomes unrecoverable, federal tax law allows a deduction for a business bad debt that becomes wholly or partially worthless during the tax year.2Office of the Law Revision Counsel. 26 USC 166 – Bad Debts The IRS allows the deduction only if the amount was previously included in your gross income or represents cash you paid out in the course of your business.3Internal Revenue Service. Topic No. 453, Bad Debt Deduction
A vendor overpayment that started as a legitimate business expense generally qualifies. You paid a vendor for goods or services, the excess became a receivable, and when that receivable proves uncollectible, you can deduct it as a business bad debt on the applicable return. Sole proprietors claim it on Schedule C. Document your collection efforts thoroughly; the IRS expects evidence of a reasonable attempt to recover before the write-off.3Internal Revenue Service. Topic No. 453, Bad Debt Deduction
If you issued a 1099-NEC or 1099-MISC that included the overpaid amount, the correction depends on timing. A refund received in the same tax year simply reduces the total reported on the original form. A refund in a later year is more complicated and may require a corrected form for the original year, which can trigger amended returns on both sides. Check with your accountant before amending a prior-year 1099.
Don’t Let a Credit Sit for Years
If a vendor holds a credit memo or owes you a refund and neither party acts, that balance can eventually become reportable as unclaimed property under state law. Every state has an unclaimed property statute, and vendor credits, overpayments, and unapplied cash all fall within the definition of reportable property.
After a dormancy period, typically one to five years depending on the state and the property type, the holder of the funds must attempt to contact the owner through a due diligence process. If the owner doesn’t respond, the funds go to the state. Most states don’t exempt small balances, though due diligence notification requirements often only kick in above a threshold of roughly $50 to $75. Either apply the credit against a future invoice, request a refund in cash, or close it out in writing. A credit you forget about can become a forfeited asset once the state takes custody.
Preventing the Next One
The single most effective control is three-way matching. Before any invoice gets paid, three documents have to agree: the purchase order, the vendor’s invoice, and the receiving report confirming the goods or services actually arrived. If any of the three disagree on quantity, price, or description, the payment holds for review. That catches duplicate invoices and incorrect amounts before the money moves.
Configure your AP system to flag any incoming invoice that shares an invoice number, vendor ID, or dollar amount with a recent entry. Duplicate-detection rules catch the most common human errors instantly, but only if they’re maintained; vendors that change invoice formats or get assigned new IDs slip through outdated logic.
Segregate duties so the person who enters an invoice isn’t the person who approves the payment run. That independent review catches errors automation misses, especially overpayments on otherwise unique invoices. And reconcile vendor statements against your AP ledger monthly. If overpayments keep turning up during those reviews, the upstream controls need tightening.