VODACOM *****ING MY MONEY

I have been receiving the following meassage for the whole year every week!!! I don't know where this comes from and I have treied cancelling it before. SHOCKING VODACOM!!! \Your recurring R7.00 Subscription to AirG Social Service will be billed on 2015-04-07. To unsubscribe click [URL Removed] :)". I clicked on unsubscribe and found I had a 1 week free trial on my accound after which I would be billed R7 per week!!! I have never in my life heard of airg nor subscribed to anything via my phone. How does this happen vodacom? PLEASE SORT THIS OUT ASAP!!!"""