Unauthorised upgrade of my contract

CellC network has upgraded my contractor further 24 months without my consent and authority and now they are refusing to cancel the contract. I have been attempting to cancel the contract for almost a month calling their call centres but I am being sent from pillar to post , no one seems to want to assist and I have lodged a ***** query but still to no fruition.what CellC has done amounts to ***** but they don’t want to take responsibility. They have been *******ly billing for the contract which I did not even know of as I had called to terminate the contract a month after it had lapse but to my surprise it continued to run. I sick and tired of CellC and their total disregard for me as a client who was wronged by them. I can be contacted on *** for more information