Overpayment letter from the unemployment office - any advice?

The agency says I reported earnings incorrectly, but I think I followed the instructions. I worked as an IT help-desk technician before this. I did not notice any errors at the time.

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.

Collect your pay stubs and certification records for the weeks they name. Mine showed the error was a date mix-up.