The road you should take is straight to the NSW Office of Fair Trading, download a form from their web site and read up on it in several areas here in Flat Chat and the OFT web site. Unfortunately you will HAVE to seek mediation as an initial step.
You have the bones of your submission here, if not all of it, but my view is just put in the bare minimum. Keep some of your powder dry for the next stage if it gets to that stage but probably they’ll just remove all heir stuff.
On the downside, you’ll be persona non grata for a while and it’ll cost you $78 to seek mediation and you won’t get it back.
You are in the right.