I have my email account with Cox Communications mapped to my iMac desk top via Office: Mac 2011 and to my iPhone.  During the day when I am away from my iMac, I receive a number of emails on my iPhone.  When I come home and check the emails on my iMac, some of them are not there.  I want to make sure every email sent to my email address shows up on my iMac so I can save in .pst files or whatever.  What could be causing this problem?  It's very frustrating not knowing what emails you did not receive.  Thank you.