Buy Now Repair

My webpage: [login to view URL] is within an iframe on our WordPress website. Our Buy-Now page receives information from the customer and determines the total price (all increments or decrements to the price are in multiples of $20). When the customer clicks the “proceed to purchase” button they are sent to the shopping cart page relevant to the total price selected by the customer. For instance, if the item price is $440 and the customer adds a $20 option for a total of $460, once they click to proceed to the shopping cart they are sent to the $460 shopping cart page. The program also emails us the customer’s selection. Currently, the WordPress files are on [login to view URL] (.com) and the iframe receives from: [login to view URL] where the [login to view URL] and mysql database are located. I wish to move the files, database and functionality from the .us site to the .com site and eliminate all files and function on the .us site. This may work best to make the Buy-Now page a WordPress plug-in or simply keep it as an html page that looks like the WordPress site; I don’t care as long as it functions and is not difficult to modify. The “logic” of the page is primarily built into the php programming with some of it covered by the database/table. I attempted to copy from the .us site to the .com site and that can be seen at: [login to view URL] This page is not functional; I am not a programmer so not sure what needs to be done to make it work or if it is even worth the effort. I had another programmer working on this and he got as far as developing a plug-in that can be seen at: [login to view URL] This page works somewhat but is still not functioning completely correct and it is not associated with the correct copy of the database. Unfortunately this programmer just quit working for me; no notice and doesn’t respond to my email or skype. He was being paid for his work so I have no idea why he quit working or communicating. I either want the current programming repaired or the page re-written, whichever will work best and/or be the lowest cost to complete. There will be additional work beyond this as well.