I never had this problem before until I believe I upgraded to 7.0.4 on my iPhone 5.
I just recently noticed that I don't have mail older than 1 week. The mail does exist on the webmail older than 1 week. I've tried searching and see that this is an ongoing problem. Is there any fix for it?
I did find Jeff's solution "Iphone - Exchange Email sync setup" dated 18 Jan 2013 This did not work for me.