Expensive unpaid fees

Please assist, I`m very upset. Last month Telkom debited my account and it was unpaid. I was charged unpaid fee for more then R200 for an unpaid debit.Yesterday my debit order did not go off. Today when I called the call centre the person who assisted me didn't help.She says I should go on to the system and make the payment. However, when Telkom could not find there money they charged me. Yet now I need to find Away to help myself. I`m very annoyed and upset that the debit order did not go off. I made arrangements with Telkom to debit my account on the 20th of each month not when they feel like It. As a customer I don’t know how Telkom systems work. They need to debit me the date a agreed on. Cause when they debited me and they could not find the funds They charged me. Yet now that they are not doing what they said they will do I don't get a refund! this is not on! Please debit my account as I have instructed.