Pizza Hut

I purchased an order of Mozzarella Sticks from this location on 8/24/2018 for $5.29. On 8/27/2018 I received a call from the manager of this pizza hut that I had been defrauded and one of them employees had charged an 8 dollar tip on top of my purchase ($13.29 total). The manager also said this happened to several other people who made purchases that day. I was assured I would receive a refund of the 8 dollars. Today is 9/7/2018 and not only have I still not received a refund, I also filed a complaint with Pizza Hut corporate and never got a response. What aggravates me the most, however, is that the person who defrauded me is still working at this pizza hut location.