Xiaomi mobile — Note 9 pro automatic close all app

Address:

Veraval.gir somnath.gujarat.india

My note 9 pro is under wareenty and it has many problems like henging, automatic close all apps, and getting home screen and screen off during using
I visited mi care service centre many time but they cant solved my problem
At this time my phone phone is in mi care service centre
And the mi care agent dont give me the original job card that i gave them the mobile phone to solve my problem
What can i do
Because no one gave me a satisfied answer
"Kya mera mobile kabhi repair nahi ho payega"