Incorrect Sales false billing

I order Router last year and it arrived with no network. I called telkom they said I must go to the nearest Telkom they said I was sold router but there is no network coverage on the city the consultant loaded that I stayed In Port Elizabeth just to get a sale. ,hence it show no service,because I don't live in Port Elizabeth. I called and cancelled the contract and they said its cancelled but until today. I still get invoice that I owe them.It also appear in my credit score have dropped because of this. I am going to take this to Aumbudsman for financial services I cannot be charged for services that were not rendered to me. *** you can contact me.