This is a good example of where the law should be changed. In Rugby (I think) they would go back for the foul / penalty etc. For some reason in football, we can't go back once we've played an advantage, but this seems to be weighted too heavily in the defences favour in my opinion. You could argue that by delaying and not signalling Advantage too soon, i'm giving the attacking team two opportunities. But I would rather punish the defending team rather than the attackers.