Overpayment letter from the unemployment office after 18 years as a data-entry clerk

The agency says I reported earnings incorrectly, but I think I followed the instructions. It has been weighing on me all week. 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.