Overpayment letter from the unemployment office after 16 years as a retail manager

The agency says I reported earnings incorrectly, but I think I followed the instructions. I worked as a retail manager before this. The letter mentions an appeal window and a repayment plan.

Thanks for writing this out. I went through something close to it last year, and it settled down once I kept a simple log of every call and form.

If you are unsure, free legal aid in your area may help for this kind of notice.