What is the term for not believing in cause and effect after death? Is it just "annihilationism"? Whatever it is called, has is always been a heresy or wrong view?

I can't see how it must be annihilationism, because the budha answers that this dogma is wrong on the grounds that we already lack a self. Unless, that is, there is no empirical self.
Annihilationism - Ucchedavada - Taught by Ajita Kesakambali

This is considered a wrong view. Here is no heresy in Buddhism but any view or notion which you have not verified empirically at the experiential level but cling onto causes misery psychologically as in Buddhism. 

Also see my answer in: The &quot;empirical self&quot; in Buddhism