I tried to call it back, and the phone co. said, no such number!

I have a new cell phone and didn't give my phone number to anyone yet but I got this call yesterday at 12.05 am. No idea who it is.

This seems to be a logal dial-out hub number for a long distance carrier (Sprint or AT&T?).  I got calls from that number coming from branch offices within my company located in the USA.  The calls I got were legit so, this isn't necessarily a scam.

I keep on getting calls from this number. When I try to return a call, I keep getting the same recording. The number you are trying to reach is no longer in service.

I think this is a free phone service called happy jack or magic jack or something - people dial into it and then get cheap long distance. Just got a call from my gf that way and didn't recognize the number at first.