Account debited without acceptance letter signed

I am very upset beyond words. There is an ongoing issue , I have never signed an acceptance letter with Bonitas. I told them I am not interested in their medical aid since I was happy with the one I had. My account is getting debited every month , after numerous emails that they have cancelled everything I am still having this issue. I am having to dispute the debit order and I am getting charged R105 every month for this. This month they debited my account again and there are really important debit orders of mine that bounced back. What will it take for this to stop. I get told that I need to provide them with my bank statement which is personal. the charges are never paid to me and if I tell them they simply say I must send my bank statement. I dont send my bank statement to anyone. Why are they deducting my my account in the first place if I have signed the acceptance letter. This is now *****