Don`t use Avis

We booked a car through Avis Uk website to be picked up in Sicily, we booked through Avis because of all the warnings on the web about using an Italian company we thought Avis would be a good way to go even though the cost of the car from them was £100 more. We thought if our contract was with Avis UK we would be safe from all of the scams we had read about. When we arrived to pick up the car we were told that they had given us an upgrade as the grade of car was not available we thought given was given not chargeable when we were also told that amounts would be refunded when we returned the car so we were not too bothered about what the agreement said as it would be sorted out on our return. Avis now say that because we signed the agreement they cannot do anything about all the extra charges we had. We were over charged by about £150 for a car for 7 days, we were charged for Personal Accident Insurance, a counter product that apparently is another form of insurance and all this on top of the all the other insurances and the upgrades. We are disgusted by Avis and at least if we had rented direct from a Sicilian company and got fleeced we would not feel so bad but to get fleeced by Avis Uk