Unfairly Charged

About 6 years ago I cancelled my debit order with Telkom mobile as they could not get my debit date correct and debited my account whenever they wanted. until last year there was no issue with me making eft payments and now I am being charged over 200 rand every second month due to a debit order rejection when I call the accounts department they say I must pay 5 days before the debit date and the extra chargers will not be there and guess what its still there Pathetic Service