[Asterisk-biz] Can some one help me to become a voIP provider ?

[Michael Young]

I actually think this is what they are trying to avoid:

/snip/
Write one or pay someone (not me) to write one. 
/snip/

Ideally, each VoIP provider would buy or write their own billing system
that did everything they wanted to do. But someone who is interested in
servicing 100 customers or less can't justify the investment.
Outsourcing is also a great idea, but is typically only available to the
largest providers at a reasonable cost. There is a reason why the Nuvios
of the world insist on billing the customer directly. 

We outsource our billing, and have written into our contract to the
outsourcing company the ability to private label sets of the bills for
our wholesale customers.

Michael