when a full tank isn't a full tank

<p>My insurer had arranged for car hire with Bidvest due my vehicle being involved in an accident. When i picked up said vehicle on the 17th May I was advised that the hold on my credit card would be for fuel and e-toll. I then asked that should i return the vehicle with a full tank. I returned the vehicle on the 16th June with a full tank ie. when i filled at the petrol station I told the attendant to fill it until the pump stops automatically. I then returned the vehicle with the guage at full. However a few days later i was charged for 12 litres of fuel - the car i used had a 45l tank - so that plus 12 = 57l. Is this possible? i contacted the customer services and dealt with a Samantha Horn who advised that they fill the tank to the brim - which i was not told. She also said that sometimes there is an airlock/settling of fuel hence the 12l.She sent me a slip confirming that 4l of fuel had been filled to the car i used prior to me picking up same. i agree with an airlock etc but to the extent that it was another 12 l ?? i was told to reurn the car with a full tank which I did. I was not shown that the car had a tank filled to the brim. To me its a double standard and would like to be refunded the fuel charge.</p>