877-227-3384

I got this call too.
He actually called my daughter (a minor) and before 8am (illegal)
I called him back and he was horrid.  (he really isn't that smart - which is a good thing)
CALL VERIZON BUSINESS AT 1 (800) 837-4966 AND REPORT HIM!!!!!
Refer to phone number #800-624-5677.
FILE A COMPLAINT!  They will shut him down.  At least on that number.
Go to https://www.800forall.com/
In the upper right hand corner, enter 877-227-3384 and the confirmation numbers (not a robot)
You'll see the history behind this number.  Note that it's forwarded from 800-624-5677.  It was registered to ring through to that number.  It was only reserved and assigned as of 9-28-2017.
Company :    VERIZON BUSINESS
Referral #:    800-624-5677
History
Status    Last Update
WORKING      2017-09-28
ASSIGNED      2017-09-28
RESERVED      2017-09-28
SPARE      2017-08-31
TRANSIT      2017-08-31
DISCONN      2017-08-31
WORKING      2017-03-02
WORKING      2016-08-08
WORKING      2015-06-04
WORKING      2015-02-13
WORKING      2015-02-12
WORKING      2014-10-23
WORKING      2012-04-29
ASSIGNED      2012-04-29
RESERVED      2012-04-29
SPARE      2012-04-29
TRANSIT      2012-04-29
DISCONN      2011-12-29
WORKING      2004-05-05
ASSIGNED      2004-05-05
RESERVED      2004-04-08
SPARE      2004-01-22
RESERVED      2003-12-08
SPARE      2002-11-29
RESERVED      2002-11-29

Call the Verizon Fraud Control Department as well.
800-880-3987

Caller said he worked for law firm representing Walmart and that i would be recieving notice to court hearing regarding a walmart account i opened in 2006 and walmart was suing me for outstanding balance of 2600. I never had a walmart credit. He started out by trying to confirm personal information which aside from my name i did not answer any remaining questions.