Telkom debit order system

I have a cellphone contract with Telkom. It has been a year now paying for this contract through a debit order. In the last two months they have not been debiting on the agreed date. October i called and they said i should go pay at Checkers because something went wrong with system. November still has not been debited and i have not received any communication from them explaining why they haven't done so.It is now inconvenient for me to keep calling then have to for a place to pay when they do not using send communication.