Account debited without my consent.

After renting out a car for a month, I needed to extend it for a further 2 days. However, I was told I needed to come to the branch and sign a new rental contract. The initial contract was fully paid for up to 10/02/2016 @ 17h00. I returned the car at 09h00 (8 hrs earlier) and signed a new contract. The gentleman at the counter told me that since I had already paid for that day , the new contract would be effective from 10/02/2016 @17h00 until 12/02/2016 @ 17h00. I returned the car at 11h00 on the 12/02/2016 ( 6 hours earlier). They inspected the car and told me everything was fine. Not more than 20 minutes after I left, R500 was debited from my account. After numerous phone calls, I was finally told that they thought I had returned the car late. It is now more than 2 weeks of constant calling and receiving false promises of investigation and still nothing. I am also still waiting for my R4000 holding deposit from them. <br>