How to restore deleted Emails from my Mails inbox?

When selecting All in a particular box, it has deleted all other emails in other boxes as well??

How to restore my emails??

I do see my emails when I click on the box, but it then flashes the page and I can not see the emails anymore??

So I know they are there but nobody will tell me how to restore my deleted emails..

Tried everything, very dissapointing Help and support is useless

Time to look for a new email provider.

[Re-Titled by Moderator]