Wrongful game subscription

I noticed an sms notifcation from the mobile-entertainment-game-club four to three weeks ago. With messages that I have subscribed for the games at the rate of R5 per day. I have since tried to cancel via the sms without success. I looked for them on theinternet and on the number provided there is no response. I would like them to remove my number on their list as I ma loosing a lot of airtime.