Custom Ajax Order Form for WHMCS

We need a custom single page order form that is separate from WHMCS and would use the WHMCS API to send data to WHMCS to create clients/orders and process them. We have some of the data such as the game name, type, slots, WHMCS product id, etc being stored in a backend database and is used to generate our current order form and simply redirects the user to the whmcs order form with the appropriate package id. Would probably need to continue to use this backend database for part of the new form we need coded. Our current order form setup: [login to view URL] & [login to view URL] With the nature of this project being an order form for a billing system proper error handling is a must. Such as if there is an error at anytime during the signup, debug information should be sent by email or other means to notify us. Since this is something custom we need to be sure customer's don't have issues with the form and if for some reason they do, we have the debugging information to see what happened and why. I have attached a list of all the order form fields we have established. Very Similar Examples: [login to view URL] (A form started by another company that was not finished for us) [login to view URL] We would preferably like someone experienced with creating ajax order forms and experience with WHMCS.