Got an overpayment notice, what now? (update)

I received a letter saying I was overpaid about $650 on my claim. I did not notice any errors at the time.

I asked for a waiver and a plan in the same call, and they gave me both forms. It was less scary than I expected.

Read the letter for the appeal deadline and act on it, even if you think you will end up repaying. Then ask about a payment plan.