I can't speak for the forfeit part, but your initial reaction should have been to run the coach when you ascertained why his batter went to the dugout. Don't forget there is a DC who is playing by the rules and not trying to pencil whip the other team through baseless clock management shenanigans.
Although, I must admit, after hearing you call out strike 2 with time still on the clock, I will have a few chose words for you as well (or at least a pitching change in the very near future
There is no way I am letting the game extend beyond that half inning after seeing what the other side is attempting to do.