False Charging

I've had R1000 worth of airtime saved up from my top up accound which I havent used. This afternoon when I tried to make a call Mtn informed me that I have no airtime left. I checked my statement and it showed that I was charged over 200 rand a day starting july for mtnplay which I have never been on since I opendy contract. There is no Way i could have used R1000 airtime in a week and when I tried to phone customers service they dont answer. I am very displeased with mtn at this moment chargin me for things I dont use and would really like my money back !