West played in 3♠ doubled by North who held ♠QJ73. Declarer leads a small club, a suit in which both North and Dummy are void. Dummy's trumps are three small headed by the 6. North ruffs with the ♠7 and declarer calls for the ♠8!. Dummy's trumps were 6 8 2 and North, seeing the top card to be the six, believed he was ruffing above dummy's highest trump. TD ruled that notwithstanding rule 41D, it is incumbent on the defenders to study dummy and no substitution of a card by North was allowed. How should the appeal be handled?