Unwanted sim card & charges

I bought a cellphone from Mr Price, and a few months ago I was called and asked if I would like to activate the sim card that I have been paying R200 for, I explained I was not even aware that I was paying for something I did not ask for. I asked for it to be canceled. I was told to go to the store, at the store I'm told to call the head office but no one who works for Mr Price knows the numbers or email address to address my complaint, I have now been paying R200 a month for a sim card I did not ask for initially, and now seems I can't even cancel the ****** thing. Please help