Apple India — complaining about iphone

Address: 1st Floor,Venus House, 908-909,Hira Modi Street, Opp.Gujarat Samachar,Ring Road,Surat-395001., 395004

Hello team,
I have purchased iphone 6s on 30th march 2019. But i have to complain about it. Two months before it has battery problem. And again it is not working, it stops automatically. Yesterday i submit it to i venus, but i am not satisfied with their service.
Kindly requesting you to provide me new handset of i phone 6s because it has two times problem within 5 months.