Redevelop website from ground up

READ BEFORE REPLYING! Personal replies will get preference over a standard generic reply that you send to everyone. We are looking to re build our website from the ground up. The Main feature about the website will be the online shopping cart. Our supplier provides us with an XML Feed updated daily to which we can build our shopping cart from and populate it with everything we need about each product. What the website needs! The website needs to include the current information/pages A shopping Cart Needs to all be integrated, look the same, have the same formatting though out the website Load fast, Look professional, easy to use, and be fancy after all we are an IT Company. Support a Help Desk ticketing system, so if a user emails helpdesk (at) [login to view URL] it generates a support ticket and in the back end of our website lodges a ticket for our technicians to reply to. Our website is [login to view URL] We have already played with Open Cart/Woo and a few others and for some reason having all sorts of issues with the shopping cart and getting products displaying correctly, pricing to be correct, etc. A test shopping cart has been setup here [login to view URL]