Consumer Redressal

I have bought one Sony Xperia Z (model no-C6602) (Imei: 35566605-727667-6) on 3rd March, 2014. From the very first day, the battery back up has been poor for the device and not running more than 4 hours a day. I took the device to sony authorised service center in kolkata, west bengal (Kalpataru Retail - Sony authorized service centre, C R Avenue, Kolkata) many a times since my purchase, where they kept the phone for few days each time in the name of servicing (as it is still in warranty period) but returned the device without any noticeable resolution. For your information, I stopped installing games and android applications as well as not able to use the facilities that smart phones of this kind generally offer. Even though battery back up remains same this is not more than 4 hours a day!!! Recently I emailed the Sony Mobile support center with the Service Request no : 1-17542907389 for which they delayed in responding for about 10 days and even after 10 days they emailed back sayin