The customer paid less than the invoice. What remains unresolved?

Give every difference a reason and an owner

Accounts payable may send a remittance advice with deduction codes that the sales team has never approved. Ask what each amount represents and where the supporting agreement or evidence is held before clearing the balance.

HMRC, the UK tax authority, publishes order-to-cash guidance that separates authorised credit/debit records from matching payments against invoices. That control distinction is useful here; it does not decide VAT, sales tax or the amount legally due on a cross-border sale.

Sources: HM Revenue & Customs: Credit notes and adjustments; receipt of payment

A receipt is not always the whole settlement

Fictional example, U.S. dollars: the invoice is US$30,000, the customer pays US$27,000, and your authorised team has agreed a US$2,000 credit for a specified issue. The remaining difference is US$1,000.

Keep proposed credits separate from approved changes

If the US$2,000 credit were only requested, not agreed, the unreconciled amount would instead be US$3,000 until the treatment is resolved. Do not create a credit merely to make the customer ledger balance.

Keep the reason, approval, document reference and tax/accounting treatment linked. Where the payment or correspondence proposes a settlement, ask an appropriate checker about its effect rather than treating the spreadsheet result as a legal conclusion.

Find the recurring cause as well as the open balance

Ask whether deductions arise from pricing errors, delivery evidence, returns, a disputed service or the customer’s own processing. Give each cause a responsible person and resolve the underlying order or data problem.

This article starts after a short receipt. Fee instructions before an international transfer belong in the payment setup, and actual tax deductions need their own evidence. Do not bury different causes in one unexplained discount account.