Which is the car rental policy for fuel?
The car hire companies usually hand the car to the customer with a full tank. You must then return it in the same way.
If you don't return the car with the tank as full as it was when you collected it, you will be charged for refuel at local price.
Depending on the company, it could be you were offered to pay the fuel in advance, in which case you will not be refunded for the unused fuel when checking out.