One thing you can check is to see if email is set to forward messages to a different address.
I don't know about other email systems but my ISP has a setting in email forwarding to keep a local copy. If this is checked the mail will be in my ISP mail AND in the forward to mail. If unchecked it goes straight to the other address and does not show up in my ISP mail.
Also, have you checked the spam/junk mail folder? Not very likely that ALL messages would end up there, but still worth a look at it.
Edited by Queen-Evie, 03 March 2012 - 09:01 AM.