Vodafone directly activating Caller tune without the knowledge of customer

I had taken a new Vodafone sim for a additional phone at 15th Aug and then used very rare.
Also I had recharged 2 GB GPRS for 30 days with it.
After 1 month when I recharge with same GPRS package. I was unable to connect. Then I call paid customer care. He told me that your main balance is negative. As they have deducted 30 rupees for caller tune which I never activated. But they have activated by default without my / customer consent.

It is just another type of cheating from Vodafone. How it is possible? What type of action I can take. If say there were an emergency and I couldn't call even I should have the balance?

Thanks