Incorrect Billing and interuption of service

I had a data contract which ended in 2014. When the contract expired I requested that the contract be cancelled. I suddenly started to get billed for data usage on this particular contract again in Feb 2017 and again in April, May and June. I queried the bill with Vodacom in April and they said that the contract was still active. I requested that they lodge an investigation as I no longer have the data card and I was not responsible for the usage. They said they would and also changed the contract to prepaid. However, this did not happen and there were more usage charges in May. I again queried in May with basically the same response from Vodacom. There were more charges in June and I then decided to go in and deal with the issue directly. They confirmed that I had requested the contract to be cancelled in April and May but for some reason it was not done. By now the account has run up to R42000 and they said that I needed to submit an affidavit so that they can investigate the matter through their ***** department. I submitted the affidavit and they said it would take 20 business days. Since July, my service on my VIP Red account keeps getting suspended due to non payment of the data contract and every time I have to spend 4 hours at the customer care centre to resolve the matter and then the whole process starts again. To date, I had no response on the investigation and nobody seems to want to get this matter resolved. In the meantime I have also bee listed on ITC which is affecting me in other ways. Vodacom is really incredibly ********* in their behaviour