Wordpress Plugin / POP3 email account integration

I have a plugin installed on my site at the moment (User Messages), which allows users to send messages to each other. Currently it is possible to send messages between users internally, but the plugin has been modified to allow users with the "parent" role to see messages which have been sent to a pop3 email account (their account is {wordpress_username}@domain.com.

The link between User Messages and the server on which the pop3 accounts are registered has been written - but it is not working and the pevious developer has stopped communicating.

Full specification is below, but in summary I am looking for someone who is able to look at the files and finish the job.

FULL SPECIFICATION
each parent has an email address {wordpress_username}@shs-email.co.uk
they don't know this exists - it is a pop3 account set up to work with this plugin
members of staff (assigned to a group called "staff" using role scoper plugin) should be able to send an email to {wordpress_username}@shs-email.co.uk, which is received in the POP3 account
the user messages plugin should go to shs-email.co.uk and check for messages every few minutes - when it finds a new message, it should be displayed in the user-messages inbox and send a notification to the "CIMY extra field called "parent's email address"
this notification should say:
"Hi {wordpress_firstname} {wordpress_surname},

You have received a new message from {name of user who sent message} on {blog name}. You currently have x unread messages. Please log on the website
({URL}

This is an automatic email, please do not reply to it."

the parents are only allowed to send messages to members of staff (no other users).... the create message page restricts them to three drop-menus which lists the names of users in the "staff" group - powered by Role Scoper plugin
when a parent sends to a member of staff, the message should be delivered to their wordpress email address {wordpress_username}@shspost.co.uk - this is delivered directly to their Microsoft Outlook as a message and appears to be from the parents email address {username}@shs-email.co.uk which allows them to respond to the email... this response is delivered to the parent's pop3 account, pulled into user-messages, parent receives notification ot "parent email" CIMY field as before and the circle continues
all @shs-email.co.uk pop3 accounts have the same password (will be supplied to successful bidder)