Called while I was busy. Didn't leave message. Number invalid when I call back

My home phone and cell phone rings at same time with this caller ID.
I think it's a co. trying to sell good numbers to solicitors.

2015649550 - robocaller that does provide opt out.  But is most likely not who they appear to be.  Let's rethink what these callers are really accomplishing.  There is some underlying technical process or reason behind these calls.  It's not just a simple solicitation call.  This is harassment, and violation of privacy.  All robocallers should be illegal, if they are for the purpose of sales, political or non-emergency calls. / I agree with other posters, that these calls are more than just simple sales calls.  LIES! LIES! LIES!  STOP SPYING ON US!  This call is either a scam artist information seeker, or something more nefarious and devious.  I don't believe any more, that this is just a robo sales call.

called my cell but didn't leave a message. I called it back and got a "end-of-call" beep-beep-beep. Then it hung up.

Spam recorded message, qualify for business loan