The company do not charge exact amount to your credit card but block an additional amount against any damage to the card if it occurs.
My Car rental charge was 400 CHF and 560 CHF were blocked against my card. When I returned the car the fuel tank was more than half filled. They have charged me for 41 liters fues @ CHF 2.95 per liter, whereas
i) Fuel tank capacity of Audi A3 is 50 liters, so there cannot be more than 25 liters of fuel space in fuel tank. But they have charged for 41 liters.
ii) Price of diesel in Switzerland is not more than 1.5 CHF but they have charged at 2.95 CHF per liter which is double the charge.
Actual charges should have been maximum 25 liters x 1.5 CHF, which is 37.5 CHF, whereas they have charge 120 CHF. This is clear case of cheating with a customer who is resident of different country and cannot come back to fight with you for 83 CHF.