You will need your remittance ID in order to repay your Social Security overpayment on Pay.gov. Social Security workers may try to force you to fill out a "Request for Waiver form" (SSA-632).You should file an appeal if the overpayment seems incorrect, you are not clear what caused the overpayment, or the SSA's numbers seem wrong. Fill out Form SSA561U2 Request for Reconsideration and mail it or take it to your local SSA office (you can't appeal online).