Debit Orders

Ever since I was under debt management and sent through the debit order cancellation form they just can't stop debiting my account. I have called a multiple time to advise them not to debit my account direct but yes They wont stop. Every month I have to deal with contacting my bank and doing a reveals of these unnecessary debit orders. Have I not paid you ? or the proper question is have you not being Paid? I have confirmed with NDA that these forms they claim they have not received were sent a multiple time to them and yet I received these stupid debit orders. I'm fed up of them I thought I was going to switch to Nedbank from my current bank. Clearly that is a bad choice.