This method would apply to cell phone users.
Verizon would have an option to create a "Unknown Caller Voicemail". The caller would not be able to leave a voicemail.
When a caller that is not on your contact list calls the number, they would hear a message: "You have reached this mailbox because
you are not on my contact list. If you must contact me, leave a text message with your name, who you represent and phone number.
I will call you back".
Those on your contact list would bypass the "Unknown Caller Voicemail".
This would block all robo calls.
I don't necessarily want the telemarketers to text me either. Also how would that work if the person calling was using a landline phone number?
I'm most definitely NOT a VZW employee. If a post answered your question, please mark it as the answer.
There are apps (and services) out there that already exist that essentially do the same thing and more....
This is not a "sure fire way" for the reason Ann mentioned, as well as many, many more reasons.
Until there is a new SYSTEM for caller identification and tracking that works for both landline and wireless there is no real solution.
It just doesn't exist yet and won't until something new is created....