Got an overpayment notice, what now? - 13 weeks in

I received a letter saying I was overpaid about $1200 on my claim. I have read a lot of threads here and could not find my exact situation. The letter mentions an appeal window and a repayment plan. Who should I talk to first?

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

Keep everything in writing and save the confirmation numbers. It made the follow-up calls so much easier.