Ahmadiyyah

Assalam O Alaikum, Sir my question is on those people who leave islam. What does Quran says about them. And is it allowed in Islam that we talk or Greet Qadayani People. Who does not accept Holy Prophet(PBUH) as a last messenger of Allah

As-Salamu `Alaykum. What can you tell us about Ahmadis? I think you can give us some insight into their ideology and method and what should our attitude be toward their missionaries.