Got an overpayment notice, what now?

I received a letter saying I was overpaid about $150 on my claim. Any experience at all would help. I did not notice any errors at the time. Who should I talk to first?

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.

Thanks for writing this out. I went through something close to it 13 months ago, and it got easier once I kept a simple log of every call and form.