a2billing DID API

Project Description:
A2billing DID api
A2billing has already an API for DIDx
we need API integrated for vitelity in order to forward DIDs to customer accounts
http://api.vitelity.net/apihelp.php
Functionalities:
1) Customer can see available DIDs (Countries,areas,numbers)
Order DID
Forward to his sip account or a number(using available dialplans ratecards,like a2b does when forward a did normally)
2)Charge per month to his account,
if balance is lower than selling price to customer number gets released from his account
else renewed
-so there is a buy rate grabbed from the did provider and sell rate that we set for the customer side
3) whatever you believe is basic function