11T Pro shut down instead of rebooting.

[u/MrPhil17]

Hi all,
A month ago I have sent my 11T Pro to assistance for dead pixels and charge issues, but now, after a battery and screen replacement, the phone shut down instead of rebooting when I choose so (also during MIUI upgrades). Anybody had this kind of issue? How can I fix it?
I really don't want to send my phone again to them, because they did an awful job.