Apple India — apple i phone 5 s..10 months old.. battery problem.. company refuse to change

I m monika.. I purchased apple i phone 5 s from amazon on 18 feb 2017.. The set is still under warranty. I m facing battery issue since from last 15 days.. The phone heat up & phone need to be charged at least 2-3 times a day. Due to this problem i visited nearest apple customer care center b2x (Pitampura, delhi). They simply refuse to solve my issue & returned by phone back. As my phone still under warranty but no body ready to solve my problem

Attached
1) copy of bill
2) copy of complaint registered