Canceling debit that I can't afford

I was ******* by the sales agent....she asked for my bank card then she told me she want to gain points and it has nothing to do with my money then I decided to give her so after two weeks my mom gave me the money for rent and I was so surprised when I got the message deduting my money from clientele life and it was R279....I want to stop this because i can't afford to this cash every month so please cancel it for me