Idea / post paid telephone connection
Wrong charges levied

I had taken a tel connection on post paid basis from Idea. Idea had provided gprs connection for my tel no which i was not knowing. the last bill i received internet charges levied was Rs 322 plus 10% service tax. the bill says that i have used internet services at morning 2.00 am on 2nd march. my bill cycle is from 23rd to 22nd of every month and the tel no is 8108335558. and is in my name Vasumathi Krishnan.

Idea says gprs is provided default and no rentals are charged, i do not understand how can i browse the net on a cell phone of Rs 1, 350???