Telkom worst sevice ever

I have a data contract with Telkom that i pay R168.00 per month they are supposed to debit the last day of the month. This month of November they debit throughout the month there is no funds in my account and i have to pay now over R400 banking fees because they dont debit when they are supposed to i have been struggling to get proper assistance. Their survice is very very bad and they dont keep to agreements made i will never do business with Telkom ever again!!!!!