Hello,
Check if the Archiving option is ON or not, because the emails get automatically archived if it is ON. Means you have a backup file by which you can recover deleted emails from PST file.
How to locate archive.pst file:
C:\User\Local Settings\Application Data\Microsoft\Outlook
and you will get an archive.pst file there.
You can also see the Archive options as it will help you to find the path of the archived file.
Thanks & Regards,
Barry Alllen