Who called from 4087154900

This number calls and leaves no message.  I never pick it up

I work remote from home and a call from this number came through the "Q" and when I answered the first time I lost the call. A minute or 2 later that number came in again and when I answered it there was a recording saying "to accept this collect call press" and I hung up. Where in the world is this number coming from and calling collect no less???

Also when I called it back a couple of times it takes a few minutes to connect and then it goes to a busy signal

408-715-4900, They call us all the time, even the early morning! Can anyone stop them?

Machine: You are receiving this message because you or a friend requested info on how you can get your contractor's license...