Unnecessary charges

Telkom debited my account before my pay date (25th) and before my debit order date, so the debit order was unpaid, on the 26th my account was still not debited, i phoned telkom and was informed that i need to transfer because they won’t attempt to debit again, i then did a transfer of the required amount, and yet my account was still debited . I reversed the funds because it was gonna be a double debit. I received my invoice yesterday, now telkom is charging me a fee of R200 for insufficient funds, how is it my fault that they debited early, and now im being told that im liable to pay that fee, how is this fair? This fee needs to be reversed because i wont be paying for something that was not my fault.