Oh, something is amiss there. The exchange rate between Australian and U.S. was 0.953133 as of yesterday: 4.6867%. How your could go from $21 to almost $40 is beyond me. I would contest the bill, if I were you. Starting with the vendor would be a good place to get an explanation and maybe, just maybe, get that adjusted.
Best of luck with all that!
Sylvain.
