Told I owe money back on my benefits (update)

After 5 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?

Read the letter for the appeal deadline and act on it, even if you think you will end up repaying. Then ask about a payment plan.