Cell C
What is happening?

I have a Cell-c contract and almost never buy pre-paid but this past week i have twice put a R15 pre-paid in and the first one went so fast that i was surprised so today 131213 i bought another one (R15) and put it in and later on in the evening decided to phone my sister so i checked my balance (it was R1 odd before i had put in the R15) and lo and behold it was R8-17 -i had lost R7 odd without making a call, now my problem is that i have joined no competitions except the Cell-C one where you answer questions but i gave that up almost a month ago and they only bill you when you answer and they have not sent me any questions for a while i started ignoring the competition and they stopped -the other spam i just delete, my problem is that if someone is my air-time then i blame Cell-C because they have the ability to stop these but it pays them to have people a persons air-time because you just replace it and they don't lose but it bugs me that people i don't know solicit me via sms and phonecall with promises of grand prizes etc -i use my phone to phone people not to receive junk mail -if this persists i am going to go back to Vodacom