cell c tech assist seems like a ****

I have been trying for like a year now to cancel the tech assist on my cellc contract, but it will not dissappear. I phone a number they give me for cancellation of the tech asssist, which is R59 a month, and they give me a reference number that I phoned in for the cancellation, but after 24 hours by which time I would have received a confirmation of cancellation sms, still I dont receive anyting, when I phone back they tell me the system doesnt show anything....... I went to cellc stores in cape gate brackenfell where they tell me they dont even know what the tech assist is, I thing all I can do now is change my bank account because I cant stop the tech assist