Was the item purchased from within Australia, or a random Chinese seller? 

If you are past the deadline for opening disputes, you can go to Paypal and open one for Not as Described.

Depending on the value of the item, the seller, and where they are located, they may or may not even want it back.

An Australian seller should send you a postage label if they want it - you must never be out of pocket on this postage. An overseas seller cannot send a label and will have to refund. Never let a seller string you along with any promises, including a replacement.