How about tell them about the fable of the boy who cried wolf. When the real wolf came no one believed him.
My argument is that JS have cried "Armageddon" so many times with false dates, that no one believes them. If it ever did come and we all died, JW would be directly responsible as that they cried "armageddon" so many times no one believed them. This makes doing the preaching work completly pointless.
This is what I say when I get the story of no one listening to Noah.
Arte:)