My fingers sometimes move faster than my brain and as a result a year or so lost all of my Emails.  I recovered them but do not remember how. 

Gradually my Saved Emails got into a mess and the list of folders or is it files on the left hand side of the panel lost their alphabetical format.  There were a series of digits in some places which when opened showed genuine folder name whilst others were empty.

I started to try to tidy this mess up but could not work out how to get the list in alphabetical order and along the way I pressed the wrong key and lost the lot.  I got an "expert" in to help and they found most of the lost folders but many are still missing.

Is there an application or whatever one calls such things that I can use to recover the lost Emails?