Incorrect Debit Order

Telkom incorrectly debited my account and I reported to be told that the amount will be reversed. It's a week now but the amount has not been reversed. It's so appalling that Telkom will deduct monies that they are not supposed to, blame it on system error and yet dragging their feet to refund. If I had defaulted on my account, would they have listed to the stories they are telling me?