Telkom and NUDEBT billing me twice!!!!!!!

I called Telkom to enquire why I am being billed twice for the current month and the agent says they didn't receive my payment for the previous month. I explained and told the agent that they debited by account using a different reference staring with NUDEBT. Agent says they cannot see the payment on the system. So will NUDEBT keep collecting the money and Telkom will continue pretending that they are not receiving any payment???