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.This sample letter has choices to help you build your letter. When you write, pick the words that describe your situation. NOTICE OF FOOD STAMP OVERPAYMENT (DEMAND LETTER) (Timely and Adequate). NOTICE. 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 salary overpayment resulted because . Open the Application for Refund; you may fill it out online, but then you must print the completed form. Sign the form in the presence of a Notary Public. § 1692a(3), in that.