wont change my debit

after calling the call centre to change my debit order date in February, I was still debited on the incorrect date, I was charged a unpaid debit, calling in again in the same month to correct the problem I was told that it was changed, again in april I debited on the incorrect date which results in unpaid debit and my services being suspended not because of my own fault but due to the lack in urgency by Telkom, I again called to confirm the change and was promised It was changed, guess what happens again this time around, I GET DEBITED AGAIN, this results in unpaid debit charges again, before I decide to cancel my services which I tried but for some strange reason cancellations is never available, I want my debit charges paid back immediately and the corrected debit date.