Gulf Gas Station ripp-off at the pump -- manipulation of transaction receipt Attleboro, Massachusetts

After prepaying $40.00 for pump #6 on Sunday April 8th, 2012 I went outside to the pump, ready to pump selected octane grade by pressing 87 (I never ever select any higher octane) and the 87 button lit up green (compared to the other two which were not illuminated.

While pumping gasoline I was certain that my tank was filling with the selected octane grade 87. I was a bit astonished when the pump stopped at 9.7 gallons while I had anticipated a bit more than 10 gallons.
On my short way home i felt something had gone wrong at the pump. The needle went only 3/4 full while a still had nearly 1/4 beore ever going to this gulf gas station. I stopped at side of road used my calculator and realized that I had been shortchanged in one way or another. 

The gas station attendant pulled the transaction receipt showing the $4.11 gallon price and I said that was not the button I had pressed telling her that after pressing the 87 it had lit up green. The attendant wanted to make believe that i had pressed the higher octane buton by error. I told her outright that I was not buying her story and wanted to speak with a manager. She said no manger ws around I asked for the assistant manager -- she said she ws the assistant manager but did not want to reimburse me.

Another atendant decided to calculat5e the price difference and gave me $2.88. Back in my car I used my calculator and again had been shortchanged. 9.7 gallon bought at $4.119 instead of $3.799 due to either a faulty pump or receipt manipulation when I returned to claim the error and asked for reimbursement.
I went back into the store another time to indicate that I should be reimbursed $3.10 and not $2.88
however the assistant manager chose to be sarcastic and I said that I would report this incident and would no longer buy gasoline at this station.

I will contact the manager of this gas station to discuss the customer treatment. Also I will file a report with the Better Business Bureau.