We received a call from this number yesterday.

im on DNC list yet they called with fake spoofed #

Leaving threatening messages that I better call them back or else..

This is from National Enterprise Systems, a debt collector (see 800-204-1819). They use 555-555-xxxx numbers in their caller id to mask who they really are.

We got a call from this number yesterday and today.  Some guy named Michael Green that says he has an important business matter to discuss. Obviously pre-recorded.  I want to know what it is but don't want to call them back because I'm sure it's nothing that I want to discuss!