Is that item # correct? Did it have tracking? Where was it coming from?

You have up to 30 days after the final ETA to open a case with eBay's MBG.

https://pages.ebay.com.au/ebay-money-back-guarantee/index.html

Edit. That second item number doesn't show up either.

I cannot find the item either (based on the item numbers you shared).

Do what Padi suggested before it is too late (don't try to communicate with the seller any more - you sent them a message and they still have the chance to reply, but don't waste any more time).

Just to add to my post. DO NOT close the case until you are completely satisfied with the outcome, once a case is closed it CAN'T be reopened again.

Good luck with that now that eBay has gone to the dogs and changed the way it handles items not received. I bought an item in January #224798317649  and no sign of item so after it was overdue I tried using Aus Post tracking to find out where it was and I got a "We couldn't find your tracking number" message.  I asked the seller to provide the right number but he refuses to do so instead using the tracking number he provided eBay to show me the item is still in transit.  Original ETA was 9Feb-18Feb then it jumped to 9Feb-23Feb and now is 9Feb-23Mar so as long as the item has not been delivered and ETA keeps moving eBay is not doing anything about it. Scammers selling on eBay can probably take advantage of that providing fake tracking numbers so bad luck if you used Afterpay, at least with PayPal you could ask them for a refund. 

Now that Aliexpress has started using Paypal and eBay is using bots to sort out issues I started using both of them to do my buying since they are both as bad as each other when it comes to dealing with any issues.

You can't name the seller on the boards, but can you find another item they are selling and put the item number or the link?

Even though it said it was located in QLD, it's entirely possible it was coming from China - many Chinese sellers put Australia as the location. One way to check is to look at their feedback page because it will tell you where they are registered.

Alternatively, the item is possibly being drop shipped.

If it is coming from China, it may still be in transit. Is there a tracking number?