Consultant did not close the contract whose fault was it?

Telkom service is so disgusting and extremely bad, I'm told that I'm owning for November and after paying for the router for 24months my wife went to Telkom shop in Galleria Mall she was told that the consultant at the shop forgot to cancel the contract so we should pay R301,70 and we did pay the contract have been closed but now we are still getting calls from Blake and associates telling us that we are owing Telkom R580. I wrote an email to Telkom asking them to send us statement for 24 months whilst the contract was active showing where did we miss payment and why we are owing up until today nothing but only call from Blake. People should try and avoid any Telkom contract their service is very bad.