I had the same experience as Peggy. They call every 2-3 weeks and when you answer all you hear is music-on-hold. This time I
left the phone off the hook just to see how long the music would last or if someone would finally respond but that never happened.
After a couple of minutes the phone went silent and I got the dial tone. I did like the music however so that's a plus for these SOB's.

Same, hold music,,hung up, I'm in Denver

Call back gets, "Welcome to Verizon Wireless.  The number you have dialed has been changed, disconnected or is not in service."  That means it's spoofed.  That means SCAM. Block it.

got two calls from this number today.  did not answer them.

called me 8/29/16, 8/31/16, 9/7/16, 9/12/16, 9/14/16, 9/15/16 - never leaves a message.
Don't know anyone from 720 area code.  If it was important they would have left a message.
Since no message was ever left - it must be BOGUS!