Hi @wilsonj1 is the VOIP lamp at least flashing on the modem/router? Have you actually plugged the phone or cordless base into the phone 1 connector on the back of the modem/router or is it still plugged into a wall socket?
Welcome to TPG Community!
What type of NBN technology are you connected?
If it's NBN FTTP (Fibre to the Premises), the home phone or base phone should be connected to the designated port on your NBN Box. Normally it should be in UNI-V1, if not, then try the UNI-V2 port.
If it's NBN FTTN/FTTB/HFC, then the home phone or base phone should be connected to the phone 1 on the back of the modem/router that we provided you.
Normally, we send email to our customers with the information about what type of NBN technology you have an also the designated port for your internet and home phone service.
Let us know if it's still not working and I'll be happy to check on it further.