Apple India — ios 11 damaged my phone

Website: www.apple.co.in

I purchased my iphone 5s in 2015 and it was working fine until i updated new ios 11. The phone is getting new issues day by day. And i am troubling with these issues. I already visited customer care also called to support but they are unable to find a solution, also service center wants charges for seeing the problem. My question is, why should i pay for this if this is the problem which established by apple.
I am getting mentally sick due to these incidents and want to resolve my phone issues as soon as possible.
But no one (Apple support & apple service center) taking it seriously.