Told I owe money back on my benefits - what worked for you?

I received a letter saying I was overpaid about $600 on my claim. I did not notice any errors at the time. Who should I talk to first?

Thanks for writing this out. I went through something close to it 10 months ago, and it got easier 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.