Vodacom is useless

Hi there. A year ago I received a call from Vodacom stating that I have not paid my account. I was quite amazed as I had 1 contract and it was paid off... I was then told that I had recently bought a phone online. I asked them where was it delivered to.. they said it was delivered to box burgh... I live in Durban.. y would I buy a phone and send it to another area? I then told them it was a ***** purchase.. the gentleman advised me to get an affidavit done n send all required docs to them to process.. I did . Months down the line I am still receiving calls from them twice or thrice a week .. I changed jobs and don't have the mail I sent to them. I informed them every time they called. Today I got a call from a lady who was very abrupt saying that she was going to black list me ... like what the hell... you'll loose the paper work... give out phones without having my ID docs and today you'll want to black list me.......... I am totally upset with this company... how do u'll employ staff that don't follow out proper checks before imitating a contract... n then have abrupt people THREATEN me over the telephone ... I want an end to this drama. I did not purchase a phone in BoxBurgh.... I do not live there... I want answers and an end to this ****