Welcome to the Community!
It appears that your issue has been escalated to our Engineering Team already after you were assisted by our Helpdesk.
Nonetheless, I took the liberty to run some tests to check this further. From what I gathered, your NBN box is actually online, however, it doesn't seem to be detecting the modem.
Please check the status of the lights on the modem itself. The WAN light is supposed to be on. In addition, if you check the back of the NBN Arris box, there should be a light indicator in the UniD port (the port where you can connect the ethernet cord from the modem). If you can't get either the WAN light on the modem to turn green or if there's no light indicator at the UniD port, try and replace the ethernet cable.
Thanks for your response.
Our tests show that your NBN box is detecting a device at least, but since your modem doesn't have the WAN light yet, that's the reason why it's not working still.
Can you post a screenshot of the light indicators on the modem?
Thanks for posting the screenshots, @Andrewbax83
It appears that there's a light indicator on LAN1. Is there a computer plugged into LAN1? Or could it be that the Arris box was mistakenly plugged in to LAN1 instead of the WAN port?