If you have medicare and you sign up for an "advantage" policy, you converted your Medicare into Don'tCare.  If you are able to get a copy of their privacy policy and are able to read the fine print, you will find that you gave up your privacy rights and gave them permission to give your number and medical info to any "third party affiliate" and you agreed to accept all the spammer/scammer robo calls.  If I inadvertently answer an unknown number, I don't say anything,  A real person will say something while a computer will hang up if you don't say hello.  If I don't know the number I don't answer.  If they don't leave a message, they are wasting my time and they get blocked.