MYDALA and VODAFONE fraud

I am using 3G data plan, but all suddenly I got a message from DM-MYDALA. Then I checked my balance had been deducted by Rs99 twice in previous month bill (November 2014) and again this month (Dec) Rs99 have been added to my bill for the same thing.I didn’t activate it either by USSD or SMS. I called the Vodafone customer care. But they told I had activated from my end. They told I might have activated it by clicking any AD pop-up while browsing internet.
I don’t remember if had clicked any pop-up ad in internet by mistake. But how come they deduct my balance without my concern. This is cheating to consumers by MYDALA and VODAFONE.