What to do when a supplier sends the wrong invoice

TL;DR

• Do not edit the invoice yourself. Once it is issued it is a legal record, and the correction has to come from the supplier as a new document, not a quiet change on your copy.
• Work out the type of error first. A wrong price, a wrong quantity, wrong tax, wrong company details, or a duplicate each need a slightly different fix.
• Ask for a corrected invoice or a credit note, and hold payment until you have it. Paying first and reconciling later is how overpayments happen.
• If the VAT is wrong, you still carry the risk. The buyer is responsible for the VAT on their return even when the supplier made the mistake, so request a replacement invoice before you file (GOV.UK, VAT Notice 700/45).
• Make sure it is an error, not fraud. A wrong invoice is an honest mistake. A fake invoice, a surprise change of bank details, or pressure to pay fast is a different problem entirely.

When a supplier sends the wrong invoice, the right move is almost always the same: do not pay it as it stands, and do not quietly fix it yourself. Tell the supplier, pin down exactly what is wrong, and ask them to issue a corrected invoice or a credit note before the bill is paid or filed. Editing the document on your side, or paying now and sorting it out later, is what turns a five-minute correction into a month-end mess.

A wrong invoice is more common than it feels in the moment. In accounts payable, anything that does not match the order, the goods received, or the price you agreed is called an exception, and exceptions are one of the most persistent drains on a finance team. Best-in-class AP teams keep their exception rate around 9%, while the industry average runs closer to 22%, according to Ardent Partners' AP Metrics that Matter 2025. Every one of those is someone stopping, questioning, and chasing a document that should have been right the first time. A genuine error has a clean, boring fix. The trap is handling it the wrong way.

First, work out what kind of wrong it is

"Wrong invoice" covers several different problems, and the correct response depends on which one you are looking at. Before you contact the supplier, name the error. It saves a round of email and tells you exactly what to ask for.

Duplicates deserve their own line, because the same bill arriving by email twice is the easiest way to pay something twice without noticing. If you keep seeing copies slip through, the real fix is less about this one document and more about catching duplicate invoices before they reach payment.

One thing to rule out before you blame the supplier: if the figures look wrong but the supplier's original PDF is actually correct, the problem may be on your side, where your own software misread a clean invoice. That is an extraction issue, not a supplier error, and it has a different fix.

The one thing not to do: edit it or pay it yourself

This is where most of the cost hides. When an invoice is wrong, the instinct is to either correct the figure on your own copy or pay it now and sort it out later. Both create problems that outlast the original mistake.

Once a supplier issues an invoice, it is a legal record, and in VAT systems you cannot silently change it. Corrections flow through a new document: a credit note that cancels or reduces the original, and where needed a replacement invoice that supersedes it, each referencing the original so the audit trail stays unbroken (European Commission, VAT invoicing rules). Editing your own copy breaks that trail and leaves your records and the supplier's out of step.

The tax case is the one people underestimate. If the VAT on an invoice you received is too high or too low, the official guidance is to go back to the supplier for a replacement invoice rather than adjust it yourself, and you stay responsible for the VAT on your own return even though the supplier made the mistake (GOV.UK, VAT Notice 700/45). Pay a wrong VAT figure and file it, and the problem quietly becomes yours to unwind.

Paying first is the other trap. Once money has moved, a correction turns into a refund request, and a refund is slower, easier to forget, and the most common road to an overpayment nobody catches until reconciliation.

What to do when a supplier sends the wrong invoice, step by step

Once you know the error type, the process is short.

• Flag it the day it arrives, not at month-end. The cheapest moment to fix a wrong invoice is before it enters your approval queue, while the details are fresh and nothing has been paid.
• Write the discrepancy down in one line. "Invoiced 12 units, received 10" or "VAT charged at 20%, should be 0%" gives the supplier everything they need to issue the right correction in one go.
• Ask for the specific correction, not just "please fix this." Say whether you need a corrected invoice, a replacement invoice, or a credit note, using the table above. That is the difference between one email and four.
• Hold payment until the corrected document arrives. Mark the invoice as on hold or in dispute so it cannot be paid automatically. A wrong invoice left in the queue is also one of the most common reasons an approval gets stuck.
• Reconcile once, against the corrected version. When the corrected invoice or credit note lands, match it to the original error, file both together, and only then release payment for the right amount.

When it is not an error: telling a wrong invoice apart from a fake one

This matters, because the response is completely different. A wrong invoice is an honest mistake by a supplier you know, and the fix is a corrected document. A fake invoice is someone trying to get paid for something you never bought, or a real supplier's details quietly swapped for a fraudster's.

Treat it as possible fraud, not a clerical slip, when:

• You do not recognise the vendor. The invoice is from a company nobody on your team dealt with, or for goods or services nobody ordered.
• The bank details have changed. New account details on a familiar supplier's invoice, especially next to an urgent request to pay, is a classic warning sign.
• There is pressure to pay fast. Anything pushing you to pay outside your normal process, or "before the end of the day," is worth a hard pause.

If any of those show up, slow down rather than speed up, and verify through a contact you already trust, not the details printed on the invoice. The playbook for spotting and stopping fake invoices is not the same as fixing an honest error, and confusing the two is how money leaves the building.

Why wrong invoices slip through, and how to catch them earlier

Most wrong invoices are not missed because the error is subtle. They are missed because the invoice is found late. It lands in an inbox among hundreds of other emails, sits unopened until someone runs payments or closes the month, and by then it has either been paid or it is holding up the close.

The leverage is almost entirely at the moment the invoice arrives. If every incoming invoice is captured and its figures laid out in front of you as it lands, you can check it against what you ordered while there is still time to send it back, for free, before anything is paid. Caught late, the same error costs a refund request, a delayed close, or a duplicate payment.

This is the part Gennai is built for. It captures every supplier invoice that reaches your email automatically, pulls out the amounts, tax, and supplier details, and keeps them in one place the moment they arrive, so a wrong figure is something you see on day one instead of discovering at close. It also flags duplicates, so the same bill arriving twice does not quietly turn into two payments.

Frequently asked questions

Can I just edit a wrong invoice myself?

No. Once a supplier issues an invoice it is their legal document, and in VAT systems it cannot be silently changed. The correction has to come from the supplier as a corrected invoice or a credit note that references the original. Editing your own copy breaks the audit trail and leaves your records out of step with theirs.

Should I pay a wrong invoice and fix it later?

Better not to. Once money moves, the correction becomes a refund request, which is slower and easier to lose track of. Hold payment, get the corrected invoice or credit note, then pay the right amount against it.

What is the difference between a credit note and a replacement invoice?

A credit note cancels or reduces an invoice that was already issued, and references it. A replacement invoice is a fresh invoice with the correct details. For a wrong amount you often get a credit note for the difference. For wrong tax or wrong company details you usually need a full replacement invoice.

Who is responsible if the VAT on a supplier's invoice is wrong?

On your own VAT return, you are, even if the supplier made the mistake. UK guidance is to request a replacement invoice from the supplier before you file, rather than adjusting the figure yourself (GOV.UK, VAT Notice 700/45).

A wrong invoice is rarely a crisis. It is a five-minute fix that only gets expensive when it is found late or handled the wrong way. The simplest way to keep it cheap is to see every supplier invoice the day it arrives, not the week you pay it. Gennai captures and organises incoming invoices from your inbox automatically and lays out the details, so errors surface early while there is still time to send them back. You can try it free, no card needed.