a website for voice broadcast,teleconference and bulk sms services

A website where users are billed through payment gateways to use these services: voice broadcasting, IVR, conference calls and bulk sms. We will use twilio API for the first 3 and a different api for the bulk sms. users will register first, receive a particular amount as test credit to try the services, upgrade to a paid service,load their online account with us to get access to our services, they are billed in REAL TIME(based on our pricing packages) as they use and can see their account balance when they [login to view URL] choose to see their transaction history with transaction dates, types and costs. Developer will also build our API for each services so that 3rd party applications can connect to their online accounts with us. we need a very wonderful design