I'm not able to call or receive call on my landline which is bundled with nbn broadband. Internet is working though. I have lodged issue on 2 September 2017, reference number 17147872. No one from Optus has contacted me with the status of issue and expected date of resolving the problem. It is NOT good enough for Optus!
Have you received an SMS from optus to say that your number is successfully ported over to NBN? Mine tooks about 24 hours. Until it is ported over, maybe try to plug in your exisiting cable modem and see if the phone is still working there.