Got a denial letter for unemployment, what now? after 9 years as a recruiter

I got a denial letter last week saying I left my job voluntarily, but I was let go as a recruiter. I would rather hear the honest version than the polite one. 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?

Keep everything in writing and save the confirmation numbers. It made the follow-up calls so much easier.