Denied unemployment, how do I appeal? (update)

I got a denial letter last week saying I left my job voluntarily, but I was let go as a customer-service rep. I worked as a customer-service rep before this. My employer's version of events does not match mine, and I have emails that show it.

Thanks for writing this out. I went through something close to it 3 months ago, and it settled down once I kept a simple log of every call and form.