CANCELLATION OF CONTRACT

I'm so ****ED with Cell C, they're Consultants are not friendly and they are doing *****, I have a contract phone with Cell C and my contract is ending on 22 October and I'm due for an upgrade, then on 27 August I received a call from one of their Consultant telling me I'm due for an upgrade and I told him I won't be upgrading anymore and I'm not interested in any phones, then after an hour ago I received a message from Cell C that my upgrade was successfully then I phoned Cell C that I received a message and I didn't agree for an upgrade and they said they will investigate my matter and escalates it to relevant people and cancel the upgrade, but when I phone now to cancel my contract they are saying they can't cancel my contract cause I've upgraded, I was so surprised how cause I didn't agree for an upgrade and the Cell C consultant did the *****, now they are busy running around i have to wait 48hrs to cancel the upgrade first before canceling my contract, and I've been calling Cell C since 13 September about they are not helping me or anything, and the consultant are not friendly and they are so rude