Bring out the relevance of Act V to the plot of Volphone

Act V is the conslusion of the play, and the place where we see the play come together. Jonson passes out judgement in the concluding scenes, the Judge is harsh, and the punishments interesting to say the least. But the ending also conserves to confuse us, as we believe our protagonist should have a happy ending (the norm), and he doesn't. Then again, he doesn't deserve a happy ending, or should we say he deserves to be punished for his crime.