How do you report hours that vary week to week? - 4 months and counting

I work some days through a staffing agency while still certifying. I have read a lot of threads here and could not find my exact situation. Pay posts on a different day from when I work. Who can I ask without risking my claim?

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.