Consumer Redressal

I purchase karbon mobile phone A20 from Riddhi Siddhi Marketing vide bill no. 5587 Dt. 18.07.2014, handset imei no. 911363750218588, this handset laying service centre from purchase date 3 to 4 month near about. I am not using frequently since purchase the handset. So I would request to kindly extent my warranty as handset laying at your service centre follow up by imei no. please give me extent warranty according company norms. Now my mobile is not working, service centre demand now chargeable basis, kindly solve issue as earliest or exchange my mobile handset.