Call blocker might be of some help. Also don't pick up on numbers you do not recognize, or where there are caller IDs that seem odd. Or where there is no caller ID.
Call from this number at 09:53 today. Since I do not have any contacts with this number and no prior history where I'd called it, I sent it to voicemail. No message left.
And, because I forgot to BLOCK this number, got a call from it just a few minutes ago - recording informing me that I WON SOMETHING! I hung up and blocked it before I could find out just what. Think the recording claimed to be from some "Green Power Survey" ...