Fed up withe incorrect billing!!

I have been having billing issues with telkom two months in a row. I have changed my debit order date. Prior months after changing debit order date there were no issues. However for the past 2 months they have been debiting my account on the 24th and my debit order date is the last day of the month or the 1st of each month. Obviously the debit order is going to be unsuccessful as there is not enough funds to cover the debit order! Then i am charged for reversed debit order for insufficient funds!! R202 per debit order!! I will not have this problem if my debit order is actually processed on the date i requested!! Contact centre keeps dropping calls and im sent each time a business link which serves no damn purpose!! I want my account fixed immediately. I am trying to honor my account and with the pandemic every penny is precious!! I am down over R400 which could have served as essentials for my family!! My only other option is to cancel my debit order and rather do eft payments