Vodafone — vas activated without my knowledge

Apparently a vas was activated without my knowledge and an amount kept getting deducted every month. Turns out the service was "activated" in march and i only got an sms in june saying i was getting charged for it.

I called up vodafone cc on june and asked them to cancel the service and refund the deducted amount. The cc person said he will do what is necessary. Turns out he never cancelled the service in spite of taking down my complaint and i got charged even this month.

I called up cc again today and the person on the line said i can send an sms "stop" to 155223 which should stop all vas activated on my number. She also said she will cancel this for me.

I sent an sms to the above number but i got a reply "you are not active on any vas service."

Then what am i getting charged for? I do not understand this scam. Who can tell me who activated the service without my approval and why wasn't it cancelled after my first call?