The most common billing errors include incorrect coding, insufficient documentation or administrative error that result in a rejected claim or a request for a repayment. If you've received a repayment request, here's what to do. 

The Centers for Medicare & Medicaid Services outlines the Medicare Part B requirements for repayment when it identfies an overpayment. 

If Medicare Part B determines an overpayment was made, a demand letter will be issued by the Medicare Administrative Contractor outlining the request for repayment and the time frame. 

When the practice determines there's been an error in processing, a report and re-payment should take place within 60 days of the determination or, if it involves past records, within six years from the overpayment receipt. 

You have 30 days to repay, request a recoupment, or file an appeal. If you haven't repaid the amount, on the 31st day, interest will begin accruing on any outstanding balance. If the balance remains delinquent, you will be turned over to the Treasury Collection Center, which could result in wage garnishment.