Apple India — Iphone 6 malfunctioning battery

Address: 122002

Website: Apple

I bought an iphone 6 for rs - 62000/ from uniworld cyber hub on 12th april 2015 which has been malfunctioning for quick discharge for last 6 weeks. I took it to the seller and he said it will need a spare battery costing me close to 6000/but they did not have. Now within 18 months of my buying a device at premium has become difficult to manage is a) expensive and b) stupid considering the apple noise which made me buy it. Prior to this my 30k-40k mobiles hae been working 3 years non stop without konking.
Can something be done??

My name: anil sharma
Email id :[protected]@yahoo.com
Date of purchase-12th april 2015