As I posted earlier. "Do not activate your voice mail".
That way no one can leave a message period.
Problem solved for robo calls, marketing, etc.
What I found with voice mail is the caller calls, leaves a message and as far as they are concerned their responsibility part of the call is done. They assume you have received and read it and acting upon it accordingly.
Only thing is If you are NOT one of those that checks your voice mail every 2 seconds, a very serious call/emergency may not be returned in a timely fashion.
Texts and only texts IMHO is the only way to converse on a cell phone. One button touch and it's all there to view and one button touch to reply. And you can block with one touch also. Something you can't do with the phone voice mail.