just received a call from this number on my cell at 1 am in the morning didn't leave message.

I just received the same call from the same number at 12:30 am . I couln't make it to my cell in time . Never left maessage . The ID said teaneck nj area

Security company offering free security systems. On the DNC list.

Keeps calling and not leaving messages. I finally had to block than.

Typical robo-dial/scammer call pattern - cell rings, do not answer, rolls over to voice mail, no message left = SCAMMER = AUTO-REJECT ! ! !

Doesn't matter if you are on DNC.  SCAMMERS and CRIMINALS choose to violate the law.  Does that surprise you?  If you think the DNC magically blocks calls, it doesn't.  Legitimate businesses voluntarily abide by the list.  SCAMMERS and CRIMINALS don't.