I had the same experience with Carhire3000 in Lanzarote a couple of months ago. The car had 60,000 kms on it and looked like it had been through Beirut. The steering was loose, and they not only charged me 45 euros for a tank of petrol (in reality 30 euros worth was all it would hold), but I had to pay the airport parking charge to get the wreck out of the carpark.
Never again !