IF your phones find device is on and you erase mi account by any professional tool or box your device will relock automatically after connect to the internet.
for fix this relock problem we have tested file for disable mi cloud will not relock also after format the phone. download the Redmi note 9 mi account relock file and follow process.
    
Download REDMI NOTE 9 (merlin) Mi Account relock fix file
REDMI NOTE 9 RELOCK FIX FILE- Google drive / mediafire link
File is paid- Whatsapp message me for file password +919595377182
How To Flash Redmi Note 9
- Download The file and extract
- Run sp flash tool And select file From location
- Switch Off your device and click download
- connect usb cable by pressing vol+& vol- in mtk port
- It will lead you to successful flashing.
If you have some issue or error on flashing your phone . you can contact us on whatsapp or facebook page . we will help you remotely (Paid Service)
 mi account relock problem . this modified file will also not relock after format the phone.){kind=link}