Thought I post this as it might help some people here going through a similar situation. Just the other week I had an eBay buyer/scammer buy a brand new and sealed earbuds off me and then claimed it was faulty. I accepted the return and he ofc ended up returning a unit with a different serial number.
Not that it's going to really matter anyways in an eBay dispute but if possible I always take notes and pics of the serial numbers of high priced items I sell just so that I know what's what. It's way too easy for scammers to do this sort of thing on eBay and get away with it and I'm pretty sure they are well aware of that. It has happened to me in the past as well.
If you are in a similar situation there is however a way to protect your funds. Just contact eBay and ask for them to email you a statutory declaration form (online help chat should be able to do that now). Fill it out and get it signed and witnessed by a JP asap and then follow the instructions provided to add it to your case.
Give it a couple of days and if you still haven't heard back again get on eBay online help chat (during business hours) and let them know that you have already added the statutory declaration to the case and they should be able to sort it out within a few minutes.
Mod: Poll with multiple options for the same thing, written in a different way, removed.
You have the (profanity)er's address.
Get the Bikies on the buyer!!!