Got a denial letter for unemployment, what now? - any advice?

My claim was denied after 15 weeks of waiting, and the letter says I have a short window to appeal. 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?

Legal aid offices and some workforce centres help with unemployment hearings at no cost. A call is worth it.

Keep everything in writing and save the confirmation numbers. It saved me later.