Told I owe money back on my benefits - 23 weeks in

After 23 weeks of benefits I got a notice saying I must repay some of it. I am in Spokane, in case local advice matters. I did not notice any errors at the time. Has anyone disputed one of these?

Thanks for writing this out. I went through something close to it 14 months ago, and it settled down once I kept a simple log of every call and form.