Email Problem Exchange 2000

I have a customer using SBS 2000.
The email is created by an ISP and then sent to the server using a pop connector, in turn the exchange distributes the email to the users.
I have setup a new user in Active directory users and computers. now i have looked at the settings of another user and they seem the same, this user can send email but cant recieve email?
is there something i am missing? i am desperate to sort this out. the settings are as follows
domain is ppeople.local
her email should be user@personnelpeople.co.za
i assume that in theory it should be a case of just setting up the user getting the isp to create the email?
any help would be much appreciated.