At this stage, I suggest shutting down all services, removing the apps from all online stores (so that noone gets ever charged again) and never, ever promise to be back. Noone believes you anymore.
I was an early user to newton when it was cloudmagic. I really loved app and stayed in touch with it. Why not just make it an open source like you mentioned when you first took over newton?
I paid them for the year at exactly the same time it went to shit. The lack of communication is not acceptable.