If you have a customer payment that was entered incorrectly, reverse it by entering a negative customer payment. When a negative payment is entered, it will increase the amount the customer owes you and reduce the total on the payments report.
Reverse a customer payment
Choose Customers, Transactions, Payments, Enter Payments.
Enter the same Payment Date as on the original payment.
For Payment Amount, enter the original payment amount as a negative value.
Choose Accept F9 to allocate the payment.
Choose Zero No F12 to view all paid customer invoices.
Locate the required invoice number and allocate the negative amount of the original payment to the invoice, then choose Accept F9.
