As I did mention a month or so ago in a post related to robocall I decided myself to tackle a solution to help fight those calls. I am still working on it as a side project, and 90% of the backend system is done, and probably 50% of the iPhone app done (considering to add Android support later).
It will add a twist on the way to fight such calls do it has at least a feature that differentiate it from similar apps.
If anyone will want to help beta test when it is ready (require an iPhone with iOS 10 or 11), ping me! (Email info in profile)