My employer is appealing my unemployment and I need advice asap!?

I'm worried that I will be tricked into saying something on the unemployment appeal call that will make me ineligible! I was fired without warning last month due to miscommunication. I was a salaried manager with work-issued Blackberry and laptop for communication purposes should I ever need to be off premise. I had a general contractor arranged to visit my home for a couple of hours so I took my 1 hour lunch and the contractor ended up taking longer than expected. I couldn't just leave this person in my home. I communicated to all of my employees and office managers as to my whereabouts and expected time back into the office. I was the General Manager and each of my locations had an office manager to run the offices in my absence. During the time I was at my home, I continued to work on my laptop and Blackberry (taking calls from prospects, team members, and even working on business leads/development). I was gone for approx. 4 hours (but 1 hour was my lunch). It was 100% unintentional. My employer is stating I violated PTO policy. I explained the scenario on an HR call yet I wasn't shown any grace. They took 4 hours out of my PTO and fired me. I'm quite nervous about the appeal call. Please, any advice would be helpful. Thank you!