This brief but important letter notifies a customer that he or she has overpaid you. It can serve as a very good customer relations letter.The notice will provide the tax type from which the overpayment originated and tax type to which it is being applied. Our document template is designed to make the process of writing an "Inform a Customer of an Overpayment" letter quick, easy, and stress-free. The Court must address overpayments in a support case pursuant to PA Rule of Civil Procedure 1910.19(g). Complaint Information. Please explain your complaint: Try to be brief, but be sure to tell WHAT happened, WHEN it happened and WHERE it happened. We have identified the following overpayment and are in good faith voluntarily refunding all monies collected in error.