Hertz deducting fuel charges incorrectly

It has been my unfortunate luck that a truck bumped me from behind. As my car would be in for repairs for app. 10-15 days, I had to hire a car via my insurance company. This company is Hertz. A car was brought to my place of work, and I drove it from around 12/2/2016 to 25/2/2016. The vehicle was not full of petrol when it was brought to me, which I pointed out to the two gentlemen who brought the car to me. On the day I had to return the rented car, I filled it to the brim with fuel, and drove app 2.3 kms from the petrol station to my office. The car was collected, and I made sure I pointed out to their driver that the car's tank was full, indeed it was overfull. This was acknowledged and the driver drove away. Now they are billing me R120.34 for fuel? I have sent them countless e-mails, but nobody has yet had the decency to respond to my query and the request for the full refund of my deposit. The car was also handed to them clean. I would suggest that the insurance companies think very carefully before considering using Hertz in the future.