Contract cancellation not done

I went to Vodacom customer care in Menlyn in 2016 to settle my contract and close the account. I paid R15000.00 and was told by the consultant that she would send through the cancellation. I kept on receiving statements but it showed I had a credit. On 2 June I went to Menlyn and the customer care was closed and the shop was changed to a Vodacom franchise (apparently there is a difference). I spoke to the manager to query why I was still receiving accounts and was told by him that the account was never closed by the first consultant and they cannot find the document that was sent by the first consultant as the shop changed and they dont have the paperwork anymore. He sent an email to head office to explain that the account must be closed and they lost the paperwork. On 18 August I started receiving phone calls that I need to pay R6977.00 because my account is in arrears. I went to the shop again on the 19th and was told that my query was closed and the notes stated that paperwork was needed to prove the cancellation was done last year. From the 21st of August i have been receiving two to three calls a day reminding me to make payment. On Tuesday the 22nd of August I told the agent a query has been logged and she said that a query takes 7-14days to be resolved, I then asked her to make a note that only after 14 working days they must contact me. Yesterday and today I received two calls again, i just phoned the call centre as was told by an agent to hold on as he will make a note to the collections department that there is a open query and they must stop harassing me, while holding on he just ended the call. i tried to rate the call as bad but even there the call was cut. Vodacom is a useless service provider and I will NEVER refer anybody to them. Its not my fault that a consultant did not do what was expected from her and that the paperwork was lost between her and customer care.