My phone died and when I charged it for a couple of hours, it still didn't start up. It didn't even shown the apple logo or low battery logo. It stayed unresponsive. Just a black screen. My charger works perfectly fine so its the phone that is broken.
[Re-Titled by Moderator]
iPhone 7 Plus, iOS 15
If the problem persists, visit an Apple Store or an Apple Authorized Reseller in your region for assistance to diagnose the problem.
And they could offer a possible solution.
You will first have to make an appointment due to the pandemic.
See: Contact Apple for support and service
Contact Apple for support and service - Apple Support
My iPhone doesn't start up
