Hidden billing

I got an Avis car as courtesy vehicle meanwhile my car was fixed. These are the things that have happened thus far:<br> <br> 1. I had the car for 29 days although my insurance booked the car for 30 days. Now Avis says I kept the car for longer than was approved despite them receiving an extension from my insurance. They now have the temerity to want to bill me?<br> <br> 2. I filled the car at the door step of the agents' premises now they claim they topped up with 13 liters! When I query this I am told I should have pressed the air-lock to fill it some more!<br> <br> 3. I was given a pre-populated form to sign which included so-called tyre and windscreen insurance! When I inform them about the pre-populated form giving me no choice they blame me! Needless to say, I have both a short and long term insurance which could have covered these extras. I suspect they work in cahoots with insurance hyenas and I would have thought that, in terms of the National Consumer Credit, they should declare to me the commission they receive for this. This is theft and *******.