question about my dads smartphones...

[smalltank]

So..my dad is getting his old Motorola Cliq 1 phone replaced with the T-Mobile 3g slide..it has android 2.2 so all his work emails should be coming in..he also got an iphone 5 on sprint to try out..though a few of his emails on his old Motorola phone came in that the iphone 5 didnt get..why is this?