If you have an Android phone, download a free app called TRUE CALLER. It blocks spam numbers. If one does get through, you can add it to their list, and never get hassled again. At home, I just purchased Panasonic cordless phone. It has number blocking capabilities. Less than $80 at Wal Mart
Called earlier today. Then called again in the afternoon. Exactly three hours apart. Did not leave a message. I didn't pick up because I didn't recognize the number.