I thought that three,on both counts. Strange days indeed

I'm not sure if the option for 'excluded' buyers is still around so you could add this person to it as I've not used it in several years

Maybe they changed their location to elsewhere and then changed back after buying? I've heard of people doing that to get around blocks

Or maybe they logged in to eBay Australia by genuine accident and then realised before they went to pay so logged out and back in to the correct site?

Or maybe eBay is just being an asp