Presuming your item sold to an overseas buyer, I recommend you cancel the order immediately
https://www.ebay.com.au/help/selling/getting-paid/sellers-can-cancel-order?id=4136&srsltid=AfmBOorJp...
You need to list on the AU site (with postage to AU only or you WILL be scammed) , be registered to sell and signed up for managed payments
https://www.ebay.com.au/help/selling/getting-paid/registering-seller?id=4792&srsltid=AfmBOor8JIPHV5h...
AND any payment you receive will be on hold for 14-30 days
https://www.ebay.com.au/help/selling/getting-paid/getting-paid-items-youve-sold/transaction-holds?id...
To contact eBay, go to Help at the top of the page,
When you get to the automated assistant, ask to speak to an agent
Be aware that the agents usually read from a script
