Check the bin/trash/deleted items in your email - if you haven't emptied it, or if the settings in your email program have not been set to "empty on exit" then they should be there.
They won't be in the bin of the computer.
There are 2 ways to access your email (other than loging on to the webmail option) - these are POP and IMAP.
If you use POP then the mail is taken from the server onto your computer/tablet.
If you use IMAP then the mail is NOT taken to the computer/tablet, but is left on the server, which is why you see identical results on your computer and tablet.