operating system did not respond
i'm using iphone 5s running ios 9.3.5
for the last 3 weeks or so my phone went crazy. it begun when i updated to ios 9.3.4, after i updated the ios, about 3 or 4 days later a notif pop up on my setting icon it says that i need to install the ios 9.3.4 so i did. but after that, my iphone constantly went off when i lock it. and when i connected it to my itunes, it says that my phone is in recovery mode and must be restore in order to use it.
i already tried multiple ways, but my phone wont respond in any ways. and i already restore it about 3 times now. it just wont work. what should i do?
iPhone 5s, iOS 9.3.5