Conned

Landing in London I went to collect my pre booked car...they told me that they were upgrading me as the car that they were giving me, a hybrid, would save me money on fuel as I was paying in rands. They then asked me to sign the invoice which I did, but stupidly I never checked it as, after all what could change?! Well I might as well have been given the car that I had originally booked as the difference in price would have given me enough fuel money to drive all over Europe... and not just to Wales and back and a little around London. They accept no responsibility as after all I did sign for it. Check your invoice when they offer you an upgrade...it is just a con :-(