My credit card detail has been given without my permission to 3rd party

MYgamesfun Through MTN I get billed twice a month for R3023.46 on 1 May and on 23 May R308.68. I HAVE NEVER SUBSCRIBED TO THESE GAMES. I am a 65-year-old female pensioner and am not looking at dancing girls and whatever other nonsense they say. I run the USSD code and it says I am not subscribed to anything.

I demand that MTN solve this for me and send me the contract whereby I gave them permission to block my card and to open a ***** case against this company.