Serges Sunoco Auto Repair

This location is charging more to credit card accounts than the amount actually charged at the gas pump and on the receipt. I bought gas from Sunoco on West Boylston Street in Worcester, MA at 11:30am on 10/26/13. My bank immediately called me to question a possible fraudulent charge at this location. Upon reviewing my transaction, we discovered that Sunoco charged my account $56.38 while my receipt is for $41.03. This is the second time something like this has happened at this location (last time they charged me twice for the same transaction). Also, when I call to speak to someone at this location ([redacted]) no one answers the phone and there is no voicemail/answering machine. Desired SettlementI would like to be refunded the difference of $15.35. I would also like to see this handled at the employment level. This is the only Sunoco in the immediate area. I receive a discount with my grocery shopping card here. I want to be able to trust this location.