Replying to Mail For mac

Okay so somehow my mac mail or whatever its called got deleted and i searched it everywhere on my computer and it didn't show up anywhere. then i went to apple.com and checked to see if i could download it but you can't download the application you can download things for it but not the application so then i emailed them and they still have not emailed me back (i have had to use Eountarage which i hate) and i have not gotten an email back for a week. so i called and they re routed me and it was 10 minutes later so i gave up. can anyone help me get it back, ++++++++++Karma for anyone who does