I agree with Hellosailor that your credit card company should be able to help, not necessarily your bank. It is pretty standard practice to have a sale reversed by the credit card company in situations like this.
If you are in Australia why would you buy simple items like rail fittings from the US? Aren't you in a metric country? US fittings will be 7/8" or 1".
Thanks for the info. Yes, we are metric here but our local steel supplier only carries 7/8" & 1" polished S/S tubing. I want to build my own bowrail and the price of fittings in the US is much lower than here. False economy though when the cheaper parts don't turn up.