How do I fill a fuel tank tot he brim and you still charge me

I had taken my car in for repairs and the insurance company had me rent a car from Europcar. Since I live in Midrand, I went to the Europcar branch at The Link on 30 April. I was given a Renault Clio and on 3 May, I was called and asked to return the vehicle for an exchange- reason was apparently the car was going to be sold. I was only able to return the car on Saturday (5 May) - this being after I had filled the fuel tank. The Clio was replaced with a Stepway. After checking the exterior for dents and scratches, I got in the car- the car would not start. Some men tried to kick start the car- it did not work- the lady then had to drive the Clio down to the circle to where the Stepway was in order to Jumpstart the car. I was really hesitant to take the car and asked what happens if it fails to start again- I was assured it would not have any problems-if it did I would need to call Europcar for an exchange. On Friday (11 May) Santam - my insurer said I should leave the rental car at the panel beater (Auto Body Specialists - on Richards Drive in Midrand)- I filled up the tank to the brim at the Caltex (disance is 1.2km from the Auto Body Specialists) and left the car there. The distance between the Caltex, Autobody Specialists and The Link Europcar altogether comes to 2.8km. Today I get a bill of R253 for refuelling- meanwhile both tanks were full when I left them. Where did you get this from, where did you drive the Stepway or Clio in order for it to come to such an amout. That about 2 days worth of petrol for me on the regular with a 2litre engine- how do you account for it with a 1.6litre. I have receipts of the refueling I did!