Europcar want us to fit their bill

I hired a car through kulula together with my flight and thought it would be good service only to regret it,the agent at the airport was a trainee and she was working with no supervision,at first she could not find my booking then she stated that the deposit was 13k then after some time returned and told me it was 3k,I only received a damage sheet to check against existing damages and did not even receive a copy of my rental agreement,I returned the vehicle the same day at about 12:00 and filled it to the brim at the garage right at the airport and returned it I noticed that the fuel gauge was not reflecting full strokes on the dashboard so I informed the guy that received it at the drop off bay,he advised me that these cars the electronics takes some time to reflect correctly and stated that the car would be taken to the depot where by then it should reflect correctly,I did not receive an invoice emailed to me and called the call centre a week later and told them to email me the final invoice and I was informed I was charged 40+ rand for fuel,does Europcar expect the customer to fit the bill for fuel from the airport to the depot,this is the second time this has happened!