Europcar billing services has hidden costs

My Budget car insurance arranged a car hire for me with Europcar as this is included in my policy. I was told by Budget and Europcar that I would have to pay a deposit which is refundable and it was for fuel only. However to may dismay after topping up the fuel and returning the hired car to Europcar I received a billing invoice stipulating deductions for windscreen and tyre waiver costs meaning I will not be refunded my full deposit. On hiring the car I again inquired about my depost and was also told by Europcar Cape Town airport service clerk that my deposit would be refunded. My complaint is that i am very unhappy about the fact that Europcar is refusing to refund my full deposit.