Is the NBN box mounted on the outside wall up near the roof? And is it connected to a cable that runs between power poles out on the street?
Then it might be a HFC connection.
This has a special connection plate inside the house connected to the outside box.
The technician may not want to do any work in- or outside or he might do just outside work.
You can try to reschedule since it is several days away.
TPG has prepared this on the different technologies they use.
Just make the selections as you go through.