Help Mail not showing up

[chisam14]

I have my Inc. set up to my work email account. Problem is I can open Outlook on my PC and I'll have 10 emails but only 4-5 came through to my phone. I love my Inc but I never had this problem with my BB. I need all my mail to come to my phone b/c it's a vital part of my work. Am I missing a setting (not sure how this would effect anything since some are coming through)?

 

[budone]

How often is the phone set to download mail?

 

[chisam14]

Every 15 minutes