How to Handle Invoice Disputes

Common types of invoice dispute

Understanding the type of dispute you are dealing with helps you respond appropriately:

Wrong price: The invoice price differs from the quoted or agreed price. This may be a genuine error on your part (fix it and issue a revised invoice or credit note) or the customer misremembering or misreading the quote (respond with the original quote).
Wrong quantity or scope: The customer claims you invoiced for more than was delivered or agreed. Check your delivery records, sign-off sheets and work orders. If there is a genuine shortfall, issue a credit note. If the work was done but undocumented, gather evidence.
Service not received: The customer claims the service was not performed. Your most important evidence is a delivery confirmation, signed work order, completion photo or email acknowledgement from the customer at the time of delivery.
Different from quote: The scope or price changed during the project and the customer disputes the variation. Check whether the variation was agreed in writing. Verbal variations are harder to enforce.
Wrong GST: GST calculation errors are fixable — issue an adjustment note for the difference. If the supply is genuinely GST-free (e.g. a health service), adjust the invoice accordingly.

Initial response — acknowledge and request grounds

Respond to every invoice dispute within 2 business days — in writing. Do not ignore disputes; silence can be interpreted as acceptance of the dispute. Your first response should:

Acknowledge receipt of the dispute
Ask the customer to specify the grounds of the dispute in writing if they have not done so already
Confirm the invoice reference and the outstanding amount
State that you will review the grounds and respond

Do not offer concessions in the first response. Wait until you have reviewed the grounds and your own documentation.

When the dispute is valid

If you review the dispute and find it is wholly or partially valid — for example, you invoiced for 10 units but only delivered 8 — act promptly:

Issue a credit note (adjustment note) for the overclaimed amount
If the revised amount is different from the original invoice, issue a revised invoice for the correct amount
Apologise briefly and professionally — do not over-apologise or assign excessive blame
Confirm the revised amount due and the due date

Handling valid disputes promptly and without drama builds trust and often results in faster payment of the corrected amount.

When the dispute is not valid

If the dispute is unfounded — the work was done, the price was agreed, the delivery was confirmed — respond with documentation:

Attach the original signed quote or acceptance
Attach delivery confirmation, sign-off sheets or completion photos
Reference any emails in which the customer acknowledged completion of the work
Restate the amount due and the (revised) due date
State that you consider the invoice valid and payable

Keep the tone professional and factual. Avoid emotional language. Your goal is to establish a clear paper trail showing that the invoice is valid, which will be important if you escalate later.

Partial disputes

If only part of the invoice is disputed, consider offering payment of the undisputed portion while the disputed amount is resolved:

Issue a new invoice or statement showing the undisputed amount as due immediately
Offer to resolve the disputed portion through a separate process
If the customer accepts and pays the undisputed portion, make sure your receipt clearly states it is "payment on account — balance of $X remains in dispute"

Without-prejudice settlement

For disputes where there is genuine ambiguity — for example, a verbal variation that was not documented clearly — a without-prejudice settlement offer may be appropriate. This means:

You offer to accept a lesser amount to resolve the dispute without admitting fault
Mark your offer letter or email "Without Prejudice" at the top
The offer cannot generally be used as evidence in later court proceedings
If the customer accepts, document the settlement in writing and issue an adjustment note

When to escalate

If two rounds of substantive exchange have not resolved the dispute, further in-house correspondence is unlikely to help. Consider:

Mediation: A low-cost, informal process — some industry bodies offer dispute resolution services
Tribunal: For smaller amounts (limits vary by state), Small Claims and Consumer Tribunals (VCAT, QCAT, NCAT) offer relatively quick resolution
Commission-only debt recovery: If the dispute is primarily a payment delay dressed up as a dispute, refer to Merion — our specialists can assess whether the dispute has genuine grounds
Solicitor: For high-value disputes or where the legal issues are complex

Frequently asked questions

Can a customer refuse to pay an invoice they dispute?

A customer may legitimately withhold payment on a genuinely disputed portion of an invoice pending resolution, but they should not withhold payment on the undisputed portion. If the entire invoice is withheld on a basis that you believe is unfounded, you are entitled to pursue payment of the undisputed amount. Whether a debt is disputed or simply unpaid affects the approach to recovery — a disputed debt may require a resolution process before a collection agency or court can act effectively.

What is 'without prejudice'?

'Without prejudice' is a legal term that means a communication made in genuine settlement negotiations cannot generally be used as evidence in later court proceedings. If you offer to accept a lesser amount to resolve a dispute 'without prejudice', the customer cannot use that offer as an admission that you only deserved the lesser amount. Always mark settlement offers 'without prejudice'. If a customer uses this term in a settlement offer, it means they are offering to resolve the dispute but not admitting liability.

How long do I have to pursue a disputed invoice?

In most Australian states, the limitation period for pursuing a contract debt is 6 years from the date the debt became due (the date of the breach of contract). In some states it may be shorter. If the debt has been acknowledged in writing by the debtor, the limitation period may restart. Do not sit on disputed invoices — the passage of time makes recovery harder regardless of the legal limitation period.

Should I accept a partial payment under dispute?

Accepting a partial payment is generally fine as a commercial decision, but be careful about how it is documented. If you accept a partial payment 'in full and final settlement', you may lose the right to pursue the balance. Accept partial payments on account only — not as settlement of the dispute — and confirm this in writing to the customer. A letter saying 'I acknowledge receipt of $X on account of Invoice #INV-2026-042. The balance of $Y remains outstanding.' protects your position.