Very Bad and Disgusting Customer Service and Maladministration

I had a very bad experience with Dollar Thrifty Var Rental Company. This happened after one of their customer was desparately in need of a car and she did not have a credit card nor cheque card to hire a car. I offered to assist the lady to use my cheque card for transactions purpose only for a week and the lady transferred me the amount that was taken from my account by then. The lady decided to extend the contract without informing Dollar Thrifty and myself on time. Dollar Thrifty informed me that tje lady did not return the car and that requested to deduct the amount due and I permitted them to. I then informed the lady about the incident and she requested to use my account for another week, tellimg me thay she agreed with Dollar Thrifty that the amount due for an additional weel was R2800 but Dollar Thrifty deducted more than that, from my account. That's when I realised that there were some misinformation, misunderstanding and misrepresentation in this contract. The lady went to their office asking for another contract extension and they allowed that and continue took money from my account without my consent and after informing them that my account had a low balance. I cancelled my cheque card. I told them that they cannot continue using my card and they habe to find alternative way of continuing with their transactional agreement. They ignored my request and they then few days later sent debit order to my account to debit +R900. I do not know for what reason amd on what basis. This is the abuse of consumer's rights and information.