Oh wait nevermind, it's something a lot more silly than that: Apparently Error 406 according to SE support is an issue with your bank, however if you try to enter in your card details more than 3 times and then try and use a different card it blocks your payments for 3 days. Which apparently support can't wave. Not the greatest news for an Australian where you can't buy Crysta and they don't sell timecards in stores (you have to order them online).