Why did Angela and ben bail on the movie new moon?

It appears you are asking about the actors who played Angela and Ben in the Twilight Saga, not the characters themselves. The roles of Angela Weber and Ben were played by Christian Serratos and Michael Welch, respectively.

Neither actor "bailed" on *New Moon*, the second movie in the series. They both reprised their roles in the film. Perhaps you are thinking of another movie or another cast member.

Could you please clarify your question?