Bogus Telkom mobile account

I have been trying to cancel a Telkom mobile contract that I did not even open, never had that number for 5 months now. In Feb/March I went to N1 city telkom mobile store and the gentleman went and cancelled the number in the system in my presence. Last month I called their customer service and I was told June statement / deduction will be the last. This morning I received another statement. Can someone advice how do I get rid of this bogus account?