HiPad Air rebooted to diagnostics menu, now won't boot or charge

Hello, I need Help with my Hipad AIR.
last week the tablet shut down and rebooted into a chinese Menu.
i translated it with google translate, it seems that it has been a diagnostics menu (check WiFi, check fingerprint sensor, and so one)
but i couldn’t find reboot or exit
so i let it sit on the table until the battery was empty and and it shut down.
now it won’t boot, chuwi splashscreen showing for maybe a second, then the screen is black again.
also it seems like the battery isn’t charging. no lights and no charging symbol/animation on the screen.
i tried different chargers and cables.
any ideas? was less than a Year old :frowning: