Lol, a ten second Google search shows that you quoted him studio portrait rates for on site wedding photos. (And for the record, while I no longer live in Queensland, I did for four years and worked in film the entire time. Just in case you want to argue that Google is wrong, and I wouldn't know unless I lived there and knew the industry). You're completely in the wrong to think what you quoted was fair.

Regardless, INFO: Did you confirm rate and/or have a contract? Or did you just say "I will pay you the industry standard rate"? Because if you only said that and no figure, you're Hella in the wrong, and (inadvertantly or not) tried to take advantage of a young photographer who didn't know better. If you did confirm, and if it's written anywhere, I'm fairly certain a lawyer can help you.