Propose your current situation, and I can walk you through the exact troubleshooting steps.
Open Gmail on a computer and go to (gear icon) > See all settings . Click the Filters and Blocked Addresses tab. how to unblock an email on gmail
If you went to the "Filters and Blocked Addresses" tab and the email address isn't there, there are two possibilities: Propose your current situation, and I can walk
Is this a personal account or a corporate Google Workspace account? Propose your current situation
If a filter deleted the emails, they will sit in your Trash folder for 30 days before permanent deletion.
You have now successfully restored communication with the contact. Their future emails will land in your inbox immediately.