Unauthorised cell charges

I noticed my amount of call time on my cell phone was diminishing. I contacted MTN and the assistant found that someone called Victorious Technologies was deducting R5 daily from my phone. I have no idea who they are or how they managed this as at no time did I ever receive anything on my phone in connection with it, let alone authorise it! I am a pensioner and depend on my cell phone time for emergency calls. Please try to find out who they are.