Likewise I have the a similar problem. Since my Optus landline was switched to NBN
1. My number was changeD with out my knowledge., After several phone calls the NEW number was disclosed.
2. I now cannot recieve any incoming calls on the new number .
3. Out going calls on the new number show "unknown caller"
No resolution has been forthcoming I have now waited 12 days for resolution which was told would be within 24 - 48 Hours.
how do I get some action?
Please let me know what your fault ticket number is and I'll be happy to follow up to try and help get this resolved.