Appeal deadline questions after an unemployment denial

I got a denial letter last week saying I left my job voluntarily, but I was let go as a procurement assistant. I am in Minneapolis, in case local advice matters. My employer's version of events does not match mine, and I have emails that show it. If you have appealed before, what helped you prepare?

Stay calm and stick to facts. Mine lasted about thirty minutes and felt more like a conversation than a trial.

Thanks for writing this out. I went through something close to it 8 months ago, and it got easier once I kept a simple log of every call and form.