As sandypebbles has said, please be careful about the information you post online. These are public boards, so for your own safety don’t give away any details that can be data-scraped  to build up an ID picture of you.

You can get a tax invoice from Australian sellers who are registered for GST; not all businesses are.

Unless the business you bought from has an ABN they can't issue a tax invoice, just a receipt.

Do not post your personal details on a public forum

You have just provided every scammer viewing the forum with your full name and email address

That warning banner when you post NOT to give such details is there for a reason

It could take a while for a mod to remove them

So be cautious of all the scam emails you might get