Explain how you arrived at this amount. Before you start writing the letter, think about your relationship with the person who owes the money.Is it a friend or relative? Amount of the previous year overpayment collected in the current year will be a deduction from income on employee's tax return in the current year. Fill out a Notice of Small Claim form. Mail the completed form to any King County District Court location. File Form SSA-632, Request for Waiver of Overpayment Recovery. Here are some ideas you can try when working to get your deposit back: 1) Write a demand letter. A demand letter asserts your rights under landlord-tenant law. Fill out legal documents online for free.