" I think it's sold it to me as a guest because I have to use the order email to go to the purchase - it doesn't appear on my account when I'm logged into the AU or USA page using the same email and details"

Presuming it's the seller who left you feedback.

Has the listing been removed ?

Go to your Purchase History page and make sure the See Orders > drop down box options are set to the correct timespan.

The seller couldn't have left you feedback if you purchased as a guest