Failure to cancel expired contract to ****** money from customers

I have been trying to cancel my Vodacom red advantage contract which expired end of March without luck, unfortunately they have been taking me from pillar to post n back.

They continue to bill me the same amount every month even thou the hand set is now paid off. Every time they promise to cancel my account but they never do and continue to bill me same amount.

Each time I phone them I never get consistent story why my account is not closed and converted to pay as you.

I think they are intentionally delaying to cancel so they can rip me off, unreasonably so because I have nothing binding me to them, I have given them notice more than 3 times but to date my account is still not closed.

What is strange is that they are quick to respond to renewal but when you cancel they are have lots of excuses n promises they don’t keep.