AMPM.com review: faulty cash payment machine

I paid $20 in the automatic cash machine at this gas station but the machine registered it as just $5. I immediately when in and explained this to the the attendant. He asked me to give this in writing on a paper and asked me to come back on the next Friday afternoon as that was the day the cash machines are opened. On Friday, I was asked to come back on Sunday. On Sunday, the lady at the station told me that they did not find a discrepancy when counting the money and was abusive. She would not give her name and just said complain to 1-800-ARCO.

Don't use the automatic cash machines at ARCO as their customer support is horrendous. There is no recourse if the machine makes a mistake.