Problem with Auto Europe!!!

We recently rented a car in Italy from Auto Europe/Europecar which we drove for about 10 days. On our way to Rome we stopped in Orvieto where we filled the car with fuel. Orvieto is less than 50 miles north of Rome where we intended to turn in the car at the train station. About three blocks from the train station I stopped and topped off the tank. When we finally found the rental office (Which is another story) we were told just to leave the car double parked outside the terminal. We filled out the final paperwork and walked to our hotel. Six weeks later we got a bill for nearly $60.00 to fill the car with fuel. We protested the charges but got nowhere even though we sent them copies of the gas receipts. Their responses were just short of rude and insulting, so we will never again rent from Europe Car/Auto Europe.