Additional charge for petrol with no proof

I visited the PE Woodford Car Hire on the 26th September at 1pm looking for a car. Luckily they had a car available (Toyota Corolla) which they quoted R366 for the day. I only need the car that day and returned it at 8am on the 27 September. <br> <br> All was initially fine and when we left PE the following day we experienced no issues returning the car and the staff was really friendly. <br> <br> A couple days afterwards when the rental amount was charged to my credit card, did I see that Woodford had charged R506 to my credit card instead of the quoted R366. I immediately called them to find out why the difference in the amount quoted and amount charged. A guy by the name of Naveen (or similar) then explained to me that the additional charges were for filling up the car with petrol which according to them I didn't do, and the service charge in filling up the tank.<br> <br> I then asked him about the amounts of how much it cost to fill up the car and service but these did not equate to the final amount charged. And regardless, I still had my slip from the Engen garage proving that I filled up the car. Neveen then told me that he would investigate the matter and get back to me. I call and nothing still!!