I was Airtel Broadband User for the past 3 Years, I had Static IP and it was no FUP until last month,
then they changed my plan to "15 GB 2 MBPS/ 512 KBPS"
I just called CC and asked them what is the procedure to disconnect the connection... then they asked the reason i replied as the data given is not enough and other operators are ready to provide more data in wireless

Then they called me and told they will change the plan and provide 40 GB on same rent ...
This is the Email which i receiver from Airtel
Dear Hareesh,
Greetings from airtel!
This is with reference to your email regarding reversal of the cancellation request for your airtel fixed line connection bearing account no. 700588XXXX.
We thank you for reconsidering your decision and retaining your airtel fixed line number.
As discussed on 97XXX1234, Please note that I have changed your bill plan to UL-Rapid Advantage 999 40GB (2MBPS/512KBPS) Combo Plan with effect from 26-10-2015.
We request you to reboot your modem after a period of 24 hours to replenish your revised quota and bandwidth.
Rental would be calculated on pro-rate basis for both the old and new plans.
The revised bill plan will reflect in your selfcare account from next bill date 05-11-2015.
Please do write in for any further assistance.