PORTAONE API XML

I need help designing a web service, an international mobile topup site. I have an api i'd like to use.. The project requires the following component: 1) A front end web site for Retail Clients with signup module, Mobile topup pricing listing, Topup sending request page with input for destination number and topup value and relevant USD conversion, customized home page, integration of payment gateways, integration of suppliers HTTP or SMTP API, real time currency management. 2) Database and Routing Integration: The system should be able to connect to database (MS SQL or MYSql) , checks the balance of the reseller/clients and PINs and route to supplier as per their HTTP API format with priority settings. 3) A reseler Module: 2/3 Levels of reseller structure: Distributor, Dealer and Reseller. A seperate login page for resellers. All levels of distributor will have a single currency- USD. The Dist/Resellers can send topup via web to the destination country number with their own pricing or retail price as set by the admin 4) A seperate module for e PIN: PIN/Voucher based top up fixed denominations for fixed countries like India, Bangladesh Nepal Pakistan which only admin can generate and assign under a certain Distributor with a fixed price and Distributor can then allocate to a reseller adding a markup 5) A SMS forwrader software module which will be connected via a modem whereas customers will send a SMS for topup request the already generated PINs and top up number. Once received by the SMS forwarder it will forward to the main database /billing server via http API for further processing 6) Customers will have the ability to send SMS from the portal through API of SMS service provider 7) Able to receive SMS HTTP API from authenticated sources and process the text message 7) Must be SEO optimized 8) Fully functional web portal