Thank you everyone for taking the time to respond.  

I don't think the police are likely to get involved in something this small-scale, even if the buyer did essentially defraud me (and Australia Post to some extent).  With COVID, I think their attention is elsewhere.

And I can definitely appreciate going down the VCAT route, but I think the cost-benefit ratio hinted at by *tippy*toes* probably makes it difficult to justify, especially when I could just put that time and money in to selling more items.

I may have come up with a solution, and I'll keep everyone apprised just in case it has value for anyone in the future who is being scammed the same way I am.

Thanks again everyone for being so cool to respond.