Denied unemployment, how do I appeal? after 17 years as an insurance claims processor

I got a denial letter last week saying I left my job voluntarily, but I was let go as an insurance claims processor. Any experience at all would help. My employer's version of events does not match mine, and I have emails that show it. Did you bring documents or only talk?

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