complaint against mobile company

Location/place: east delhi

Name of company/service: aircel(INQ)

i had purchased a handset from aircel company,s outlet,mobile name (INQ chat 3g) on 10-7-2011.IMEI-353872031107217.but after some time my handset got defaulted due to display and i had given my handset to service centre on 16-3-2012,but at present time the company is not responding to repair my handset at till time 6-17-2012.company people they are picking the calls and not responding properly and till time they did not repair my handset and my warranty is going to over in next month,so please tell me the suggession and procedure about this case.