Karbonn Mobiles — karbonn service center not return my karbonn k-phone1 since above one month

sir, i aninda mondal purchase a karbonn "k-phone I" mobile on 10/07/2013 with IMEI NO:[protected] . Unfortunately the phone is not working after some days(within one month). I give it my phone to service center for sevicing on 02/08/2013 with Complain No:KA[protected]. Now i request to service center to return my phone but they are not bothering at all.