Had the time to have a battle of wits with an unarmed person so I picked up on the call.  After a couple of "Hello's" no one came on the line but I could hear faint voices in the background.  The line didn't disconnect to I left my phone off the hook for about 15 minutes.  When I came back the sounds were still there.  At that point I hung up knowing they will call back and I would have another chance to play games with them.