How do I keep wanted important emails from the trash?

I keep having wanted important emails going into the trash.

I have the email address in my contacts.

I have made it VIP.

From my iMac I went to iCloud via Safari and made a rule to put it into a mailbox.

Sometimes the emails go to the special mailbox, sometimes into the trash.

The sender’s email address is always the same.

How do I keep the emails from going into the trash?

All operating systems are up to date as of today.

It happens on every device.

It happens on iOS and Catalina.

It has been happening for quite a while.

And I can’t even find Mail here as a topic so I’m making it iCloud.