contract cancellation

I have been trying to cancel my contract, I have filled a form on 16 January 2016 it is still not cancelled , I call the call centre 3 to 4 times a day but I don't get help, their price a so unreasonable, I have asked them to stop sending me data or airtime but still , they said they call me during the day, but I can't answer me phone during office hours, I asked 4 their number they can't give it to me. Pls help me people.