Hi
I am an Independent Advisor, trying to help other users in the Community with my experience in Microsoft products. Please note that I am a user like you and don't work directly for Microsoft.
I am sorry to hear that you are experiencing this issue and I hope the following suggestion will work in your case.
First, check this link:
https://outlook.live.com/mail/0/deleteditems
You will see this: Recover items deleted from this folder.
Can you retrieve your emails from there?
Also, check your Junk mail/Deleted Items folder.
If that does not work, then please reach out to Microsoft chat support:
Click on:
https://support.microsoft.com/home/contact
You will see this "Tell us your problem so we can get you the right help and support."
Type "missing emails" and select "Find and recover missing email".
***You will see an icon "Contact support" at the bottom of the page. Click on it.
Select Microsoft 365 and Office. And then Technical support.
Click Confirm.
You will see an option to start a chat in your browser with Microsoft support.
Just note that emails in the Deleted Items folder will be deleted after 30 days.
Please let me know if that helped.
Regards
Casper