Freddy's Frozen Custard and Steakburgers

I drove thru on 7/25, and after a very long wait finally ordered and was quoted a price and when I finally got to the window to pay I was again quoted a price of about $12. I paid and we left. When we got where we were going, we ate and then looked at the receipt for over $19 and with the wrong items listed. I called the store when I realized the error and after speaking to a young girl who told me she was the manager, she finally got the real manager who said I would have to come back to the store for a refund.
I don't live close enough to any Freddy's restaurant for that to be reasonable so I emailed their website. I immediately (within about 10 minutes) received a message from Dwayne, who told me that Gary or Shannon would call and give me a refund by the following Monday (7/27). I waited over a week but never heard from anyone else. So yesterday, 8/4, I emailed again and haven't heard anything from anyone.
Product_Or_Service: single steak burger/2 regular cheese curds/ice wat