We filed a 1099-C with the IRS a few years ago. The customer has since repaid the loan in full. The customer is asking the bank to report the repayment to the IRS. I know you can't amend a 1099-C when repayment occurs. What should we file?

If, included with payment of the debt, the customer paid more than $600 in interest, you would file a Form 1098 for the interest paid. Otherwise, you would file nothing.