Go to the website of the business which markets the real item and report the seller for selling fakes.  It is then up to them to put them out of business.

Furthermore if it was sent by post, but with no dangerous goods stick attached report the seller to Aust Post

If you paid by PayPal lodge an Item Significantly Not a Describe dispute now, and then as soon as you can, escalate to a claim.

If you paid by credit card commence a chargeback through your credit card provider

If you paid by bank deposit you only real recourse is to take the seller to court (small claims)