
I see this all the time. One player names trump and their partner sabotages their efforts. Yes, the team made a point but lost the game at 9 to 9.
Would you have played the same way? Well, take a look at what would have happened if East (the maker's partner) had correctly shown the maker where the left was. And then played the Ace of diamonds.

A two-point hand and at the end a win.