Make sure that your modem is plugged into the UNi d port and that the LED is on
Have you put a pin in the reset hole on the modem?
If so, you may have lost the configuration.
Do not do this if you do not know how to reconfigure the modem
You can serach youtube for videos that show how to put that back.
You will need to know your account user name and account user password (dont confuse this with yourr wifi details).
If you have no luck with this you can lodge on online fault report with TPG.com.au
You can directly connect a laaptop to the Uni d port via an ethernet cable to the lan port on a laptop.
You wont be able to use wifi, and you will have to follow the "how to set up a dialer" section of the document that I have attached. You will need to know your account user name and account user password (dont confuse this with yourr wifi details).