Appeal deadline questions after an unemployment denial - what worked for you?

I got a denial letter last week saying I left my job voluntarily, but I was let go as an office manager. I am in Detroit, in case local advice matters. My employer's version of events does not match mine, and I have emails that show it.

File the appeal before the deadline, even if you are unsure. You can gather documents afterwards. That is the one part I would not wait on.