At random times of the day, our landline rings and displays 'External Call'. When I pick up the phone, it just has the dial tone sound and when I hang up, it starts ringing again straight away. If I don't hang up and leave it 20 secs or so before I do, then it doesn't ring again. Also, when I hear the dial tone after answering, there is a clicking sound which you would usually associate with a phone being tapped. Hopefully that is just my paranoia. As it's not a number being displayed, I can't block or report it. Does this happen to anyone else? How can I stop this?
