Reliance Communications — Harassing me for bill payment for a fake bill

Address:

Bangalore, Karnataka

I had a reliance number two years back, on which the plan I took had reliance to reliance calls free.
I got my bill in the month of January 2011 and that had an amount I didn't expect, upon asking reliance for what i'm being charged they had no answer. They again generated another bill in January, that again had me charged heavily. Again the only calls I used that number for was reliance to reliance which were supposed to be free.
When I approached the reliance people they didn't have the details as to for what i'm being charged. And now they're sending me legal notice and what not make that payment of 3000 rs. I'm not going to pay this amount as till date I don't know what I was charged for (the bills were not itemized inspite of my multiple requests).
Can someone help me get this sorted out please. I had tried my best to get in touch with the reliance officials that time and they were all hanging up on me, upon my questions. And now they've woken up after two years and troubling me. Please help!