Got a denial letter for unemployment, what now? (San Diego)

I got a denial letter last week saying I left my job voluntarily, but I was let go as an insurance claims processor. I am in San Diego, in case local advice matters. My employer's version of events does not match mine, and I have emails that show it. Did you bring documents or only talk?

I printed my emails in order and wrote a one-page timeline. The hearing officer kept going back to it.