Shell

I was at this location on 8/20/2019 at 00:59 hours. The cashier scanned my items and the total was $20.87. I paid by Mastercard and was approved. I received an Auth# 020779 and the cashier thanked me. So I went to my car. 30 seconds later, the cashier came to my car and said that my credit card was not accepted. I told him that it was approved and I received Auth # 020779. His total was still on the screen and informed me that his register is using a new system and was not able to accept my credit card. I used another Mastercard and received an Auth # 010020. I received an email that I was charged twice for a total of $41.47. I talked to the owner of this Shell Station and he told me that in a few days I will only pay $20.87. Well, I waited a few days and still was charged $41.47 and now the owner refuses to pay me back the $20.87. The owner tells me that he has been doing business for over 20 years and that he trusts his cashiers. The owner doesn't know that I have worked at a Shell Station for 30+ years and managed 3 stations in the past. I don't trust the owner or his cashiers and I will never go to this Shell Station again cause I do not want to pay extra again. The owner does not know how to treat his customers right and this is how you lose customers.