Bestop Gas Station

I was curious about the gas prices here considering that around my area is $0.20 more expensive. I decided to check it out today before going to work so I purchased $25 of gas and ciggs totalling $30.00. Unfortunately for me, my car only took $21.25 to fill so when I went back in the store to ask for a refund, the associate refused "I do not give cash back." He said I can get something for $3.75. When I looked around the store, the frozen smoothies were melted, sodas were warm, and everything else was either deep fried or frozen solid. I wanted to ask him if he can put it on my card since I paid with my credit card, yet he still refused and started yelling at me. I don't know what the store policy is, I just want my money back... it's just too bad that these people steal money from their customers if you decide not to buy their low-quality/abused merchandise. I definately wouldn't recommend this store to anyone, the customer service is extremely poor and so is their choices of food and beverages.