Overpayment letter from the unemployment office (Portland)

After 2 weeks of benefits I got a notice saying I must repay some of it. 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?

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

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