Overpayment letter from the unemployment office (update)

The agency says I reported earnings incorrectly, but I think I followed the instructions. The letter mentions an appeal window and a repayment plan. 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 9 months ago, and it got easier once I kept a simple log of every call and form.