redx, I have no idea what the credit card and consumer protection laws in Oz are, but they must exist. I would suggest exploring them since there are often 30 or 90 day periods that cut off recourse. If your bank cannot explain why they cannot begin a chargeback procedure (or whatever it is called down there) surely there are some "consumer protection" agencies or something like that to help you find and use your rights.
The google business is odd, but I've also learned not everything on the web is what it appears to be, and Google is far from infallible. Something is wrong with this picture, but once you know the procedures it should no be hard to straighten out. Oz can't be that far behind the US in protecting consumer rights.
My thanks go to everyone who replied to this thread. I have revisited my bank and explained the situation and given them all the details. This time they have initiated a dispute through my cc company which they say can take up to 45 days to resolve. Hopefully, something positive will result.
I might add I have not yet lost faith in shopping with US companies, I have had some excellent service from several in the past and am impressed by the quality of the products purchased.