Bad service

I have been trying to cancel my vodacom line in the beginning of November and was offered a deal to upgrade which I accepted but changed my mind and decided to cancel. I was told first it takes 3 days and then told i have to wait till end of the month to cancel due to the migration and spoke to 3 agents who gave me 3 different stories. The last agent told me the migration should of been cancelled but it was not and that she will escalate and her manager will call me on that day which was on the 30th Nov. Im now done with phoning and getting different stories. I want this line cancelled as agreed effective 1st Dec and any account credited where due.