Hello, first thing first sorry for my English. Here I have a problem with my iPhone 6, after updated to iOS 11.4 last week my iPhone is now a corpse. Here a complete story; my iPhone won't charge it battery unless when turned off or when it over heat (triggered with playing snapchat filters), so previously I have it with iOS 10.3.3 and my iPhone do restarting by itself if I operating it quick after turned on, to make my iPhone usable I need to keep it locked with airplane mode on for at least 12 minutes then viola my iPhone working fine (no more restarting). So long time ago after iOS 11 released, I tried updating and then my method not working anymore, so I quick downgrade back to iOS 10. Every time my iPhone have iOS 11 downloaded it makes restarting issue more triggered, so i deletes iOS 11 whenever it downloaded on setting. Last time, the newest iOS 11.4 downloaded and my iPhone didn't have response like before, it's not trigger restarting issue, so I thought it must be fine now. With hope that it's already fine so I decided to install the update, but... oh no... now the actual problem has come, my iPhone restart every 2 minutes and few seconds, no matter how long I keep it in airplane mode and locked (not used/operated), the iPhone only able to use maximum to 2 minutes and few seconds, after that it will restarting by itself. So the final question from me, what's actually happened to my iPhone 6? does anybody facing similar issue? can it be fixed? and how much it cost? please I need the answers as detailed as possible, because i tired of googling it and has no clue until now. Thanks for reading, I'm waiting for your help.