I look at caller id and if I don't know the number or it is an 800 or 866, I let it go to answer machine. DOn't waste my time. If you can get their address you can send a "cease and desist letter" and tell them to cease and desist in all calls to your phones. By law they stop. Works for me. I tell them I need their address to send them something and then send the letter instead. LOL. So sorry. I know they can be a pain.