If i understood your question, the answers can many and for this i inviate you to see this link...
Here some steps:
Gmail messages are missing
This page can help you find your emails if:
Some emails are missing.Emails aren't coming to your inbox.Your inbox is empty and all your emails have disappeared
Emails might skip your inbox if they were accidentally archived, deleted, or marked as spam.
Follow these steps to search all your emails, including those that aren't in your inbox:
1 On your computer, open Gmail.
2 In the search box, click the Down arrow .
3 Click the All Mail drop down, then select Mail & Spam & Trash.
4 Enter some information that’s in the missing email. If you're not sure about exact words or details, leave the fields blank.
5.At the bottom of the box, click Search
Check if the email was filtered
You may have created a filter that automatically archives or deletes certain emails.
Here's how to check your filters:
1 From a browser, open Gmail.
2 In the top right, click Settings Settings.
3 At the top, click the Filters and Blocked Addresses tab.
4 Look for filters that include the words "Delete it" or "Skip Inbox."
5 To the right, click Edit or Delete.
6 Follow the on-screen instructions
Other istruction are on the link above