Vodacom refuse to cancel the contract

I have a problem with vodacom after a four year contract with them, they have been refusing to cancel my contract this year, it's been 5 months now. My contract actually expired in May this year but extended to September without my knowledge their reason is the account was in areas July so it automatically extended to September, I was not aware about that but i made a payment later. I called on July after payment they said its not reflecting and and i have wait for 2 days or so, I called again they said they will cancel it but they didn't. I called in Aug i couldn't get any help then called again in few days then. One lady who was very helpful managed to assist me and to pay again and extra amount if I still want to cancel, given 14 days to pay R164.793 and even had a reference no: ***. I was told my told my account will automatically be cancelled after paying that money but it wasn't. I got invoice last month then called again and they said they will cancel it but they didn't. Now they blocked my number and i got an invoice requesting money and i don't even have it because I'm not working. Most of the stuff in cancellation department are not cooperating and have been very rude, in a way that they will tell you they dont work with cancellations and refer me to another person who is not is also not helping and asking me why i referred to them because they are not working with such matters, their only interest is to renew the contract, and telling about me about what's on special, I sent 2 emails to their customer care but i never got any help. Please help me, because even at the branch they can't cancel this contract i have been twice regarding this matter