Got an overpayment notice, what now? - 3 weeks in

The agency says I reported earnings incorrectly, but I think I followed the instructions. Any experience at all would help. I cannot afford to repay it all at once. Who should I talk to first?

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.

Keep everything in writing and save the confirmation numbers. It saved me later.