How do I turn off the handsfree mute? I used it for a conference call and after the call was over I cannot get it off mute. When I choose a line the handsfree mute button automatically comes on without me pushing it. I have pushed it to try and turn it off after choosing a line and it blinks as if it were on hold and says "microphone muted" on the display screen. I cannot hear a dial tone at all.