It sounds like you were viewing the North American lodestone. Lodestone displays information based on your browser language setting. For example, if it is set to "en-us" (English - United States) it will display the relevant information for North America. If I change my language setting to "en-au" (English - Australia), this is what I get when I look at the "price discount" post you are mentioning:
http://i.imgur.com/BPpOU.jpg
There was no deception here. I'm not going to white knight them though, SE erred here in trusting language preference instead of offering a traditional manual region selection. Most likely the representative you spoke to was clueless about what was going on and assumed you had a different issue, which is also hardly excusable.
That issue aside I'm curious why it lists GBP as an option for Australians if it didn't let you convert to pounds for your payment. That would have saved you a lot of money since they more or less properly value the pound while woefully undervaluing the Euro.