Are the emails being checked directly from a pop server or an exchange server?

Is this Intranet email or Internet email?

One thing I can think of is if they use email in the office have them setup a rule to forward email to an Internet Based account and check it through gmail/yahoo/hotmail.

Simple and sweet.

http://e-mailanywhere.com works great as well, No server info needed in most cases. However if they have 25/110 blocked it may not work.