Received a call from this particular number and CID displayed "portfolio recov" 779-752-4214 and as usual no VM was left. Since no VM was left, the call wasn't important to begin with. I won't call the number back to find out why they are calling either, as that is what the answering machine is for.
Other numbers that they use are:
407-380-1234 - Florida
312-494-3452 - Chicago
770-405-0306 - Georgia
760-760-9041 - California
404-889-8269 - Georgia
770-752-4215 - Georgia