Can't delete old email

I can’t delete old email. I’ve tried to delete them according the rules, but no use.

What happens when you try to delete messages? What rules are you using?

Normally I click on the email and delete it. It’s deleted but appears always again.
Then I use “searching email” on date or name… and I delete… but it appears always back.
Not all my deleted emails have that problem but only some older emails.