It was actually part of my order that surprisingly went through. Sorry about that.
I see that it was an NXXT cross trade. This means that my broker (Commsec) had a buyer at this price and in this case they can choose to buy from another Commsec client instead of those equally priced orders from other brokers (as long as there are no better offers on the market at that time).
I think it's unfair (which is why I starting this thread) but have checked and that's the way it goes.