Custom PHP Email Management

We have a company that sells via Websites and also eBay. The eBay selling generates a HUGE amount of emails that we need to deal with. We have written some code that automates many responses, but many questions need to be handled by customer service. The concept is to create an email client that would parse the email and retrieve the customer/invoice/product data and then allow Customer Service to see all of this at once on an HTML form. Probably with some canned responses from the data with the ability to edit/add. We have a PHP class library that talks to our database (Which is NOT SQL) as a start. This project should probably be built using one of the open source PHP email clients as a start. What we are looking for in bids is not just a price, but also experience in email management and/or communications with specialized databases. Ease of communications are also important, we envision that this will not be managed just by emails, but also by phone [login to view URL] personal contact.