This figure provides details of what is found in the 510-C letter. The details include the IRS address, date of the letter, name and address of the taxpayer, taxpayer's TIN, form number, tax period, salutation, amount of the erroneous refund, method of payment, date of the erroneous refund, an explanation of what caused the erroneous refund, amount the taxpayer needs to repay, and the IRS point of contact.