Telkom charges

I have cancelled my contract with Telkom a month ago. There were no cancellation fees needed due to it being on the end of the contract period. They tried then to deduct R1200 in the middle of the month (my debit orders are for the 1st of the month). Of course I do not have R1200 in the bank at that time and they added R200 due to failed debit. Now they tried to deduct again and they will add R200 again. This is unacceptable. My bank also deducts R80 per failed transaction.