Told I owe money back on my benefits

After 18 weeks of benefits I got a notice saying I must repay some of it. It has been weighing on me all week. I cannot afford to repay it all at once. 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.

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