You wouldn't deal with an uregistered builder? So why risk dealing with an unregistered telco?
Every Australian based telco is required by law to be registered. The Australian Communication and Media Authority (ACMA) administers the registration and lawful compliance through its delegate Communications Compliance Ltd (CommCom).
Avoid losing your consumer rights... if you're thinking about dealing with a Telco Provider that does not display the CommCom logo then think again. You may lose your consumer rights if you signup with an unregistered telco.
TIP: Only deal with Australian based, ACMA compliant and CommCom certified Telco Service Providers, like FYI Telco, who display the CommCom Member Logo on their website: (no logo - walk away)