Welcome to TPG Community!
We failed to locate your account using your community details to check on what type of NBN technology you have.
Once the NBN is installed and activated, the old WiFi will be disconnected, since the one that will be used is the new modem that we provided you.
We've created some articles that will guide you on how to set up your new NBN service.
Here are the links:
Should you require further assistance, please let us know.