Time you brushed up on defamation law in Australia. You cannot...

Time you brushed up on defamation law in Australia.

You cannot defame a government department.

And

"A person cannot recover damages for defamation unless the defamatory statement sufficiently identifies that person as being referred to in the statement. For example, it has been held that if a person stated that all lawyers were thieves, no particular lawyer could sue that person unless there was something to point to that particular individual lawyer."

https://www.ags.gov.au/publications/legal-briefing/br28.htm

Once again your words have been judged, and found wanting.

You could be sued for defaming that poster by claiming they are defaming someone else!