Hey Lsub,
Welcome to Crowd Support
I'm sorry to hear of the issues with this activation being completed and it does sound as though you have tried all of the details that we have listed for this issue at:
We do have some following steps that you can try with the WiFi connection from your modem at:
https://crowdsupport.telstra.com.au/t5/General-Internet-KB/How-To-Troubleshoot-WiFi/ta-p/107516
If you can't get the WiFi signal to connect to this device then the next contact is the Telstra TV Faults team on 132200 (24/7) and saying 'Telstra TV' and then 'Faults'.