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 Maricopa County Treasurer's Office is to provide billing, collection, investment, and disbursement of public monies to special taxing districts. If DES gives you too much money or too many food stamps, it is called an overpayment. How do overpayments happen? The salary overpayment resulted because . Our document template is designed to make the process of writing an "Inform a Customer of an Overpayment" letter quick, easy, and stress-free. We have identified the following overpayment and are in good faith voluntarily refunding all monies collected in error. Business owners must pay their renewal fees when they submit their renewal. Tens of thousands of Arizonans have learned that they have to pay back their unemployment to DES, due to no fault of their own.