Security Deposit Not Returned by Airtel (Airtel Number: 01143090565_dsl, Account No 14712171, Name of account owner-Girdhar Gopal Maheshwari , Mobile No-9650003547)

This is to inform you that i have disconnected my above airtel connection 2.5 months back & returned all the equipments related with this to airtel.. It was communicated to me that i will get my security deposit check that i have submitted at the time of taking connection within 15 days at my address. Now it's more than a two months & i haven't got any refund from airtel. I have already mailed them once but still i haven't received my security. Kindly take some action against them so that i can get my security back