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.Download our most commonly requested forms. NOTICE OF FOOD STAMP OVERPAYMENT (DEMAND LETTER) (Timely and Adequate). NOTICE. Clearly state the decision regarding the refund. This form is for general instructions that apply to all corporation tax forms. It includes a variety of topics about how to fill out your form. We have identified the following overpayment and are in good faith voluntarily refunding all monies collected in error.