Karbonn Mobiles — I have not received my phone from service center

My Karbonn phone model A3 IMEI - 1 :[protected]; IMEI -2 :[protected] went dead so took it to the service were they deposited it on[protected], under guarantee job sheet no. being KJASPDL108314K7713. After five months they gave me a faulty replacement model A51 IMEI/ESN1 : [protected]; IMEI/ESN2 : [protected] which never switched on, so, returned back to the service center and the incharge of the center Mr. Gaurav after issuing me a new job sheet no being KJASPDL108814K13610 gave a personal assurance that he will give me a call back and took both the hand set and battery leaving me with the flip cover. Now the phone at service center is not ringing (there is always fault), the executives at the customer center are rude and they keep disconnecting my phone, though they gave me some numbers for few interaction, they are 60676 & 135818, with the second number executive said that I'll be getting a call back, which I'm still waiting for. Kindly help me get my phone back in running condition.