Sonic Drive-In review: money/credit card issues

On two different occasions I've visited this sonic and paid with cash. On both times when they gave me my change it was short. When I brought it to their attention they made up some excuse like where we were all out of nickels or pennies or something of the sort. Then a couple months ago while getting ready for work in the morning, I received a text message from my credit card company saying my credit card was just used at this sonic location. I had my credit card with me so whoever ran the purchase must have stolen my credit card information off of my card at one time. Today I visited there with my mother and we paid with her visa credit card. She later noticed that the receipt that they gave us had the correct amount but it said we paid with cash and even noted the amount of change they gave us back. I will be watching her credit card very closely are As I have to wonder if it is not your employees that fraudulently used my credit card a couple months ago.