'Unknown Caller' on my caller I.D. called from 551-323-9000, I said 'Hello.' Nothing but silence on other end of the line, I hung up, picked up phone to punch in my phone company's call blocker code and line was still open 3 mins later, no way for me to block them on a still open phone connection. Picked up phone after 10 mins, got a dial tone, punched in my code and that # is now blocked 4 ever. 9:50pm is a BS silent phone pest/prick lock-out until perp hangs up. Consider adding this to your call blocked #'s.