I purchased gas from Sunoco gas station on Lancaster avenue in Ardmore to fill up my gas tank which usually costa me $45 dollars. I chose 87 octane grade gas and placed the pump in my tank. I got back in my car to put my bank card away then returned to the pump to find that the pump was giving me 93 octane grade gas at $3.99 a gallon. After stopping the pump I went inside of the gas station to tell the attendant what happened and he seemed to already know telling me to follow him so he could show me. Clearly this was not the first time and I wasn't the first person it has happened to. The attendant walked over to my car lifting the gas nozzle and bumping the gas tank with the pumps hose which selected the 93 octane grade of gas. Then he told me it was human error and that it would not hurt my car. The attendant basically blamed me and did not adjust my receipt for the pump error.