Welcome to Justanswer.com, my name is ***** ***** I will do my best to assist you.
The question we need to answer is, were the messages simply moved to a different folder or were they deleted.
You should try doing an all mail search, by using the search bar above the inbox. Also search the trash and see if any of the messages are there.
If you cant find the messages in either location, then you have only one option. You need to review the page below, follow the steps.
And then click where it says file a report. Gmail will attempt to restore any deleted messages, but there's no guarantee they can. ( It depends on time, how long ago they were deleted, and random luck)
If you encounter any issues completing the steps I mentioned, or the steps on the page. Then you are welcome to reply and I will assist you further as needed.
I strive to provide great service, and greatly appreciate a rating of excellent ( 5 stars ) selected and submitted below this answer or at the top right of the screen. I always answer follow up questions.
Senior Technician and Network Switching Systems Operator / Maintainer.