Keep getting calls with no answer

Multiple times a day. When I call the Number back, it's busy each and every time,

multiple calls, call back and all i get is a busy signal or your call can not be complete at this time

THEIR STILL AT IT! multiple calls daily for three days now, when I first answered there was silence on the other end,  now we just let it ring because checking it out gave us either a buzy signal or a recording saying that the " call can't be completed at this time".  This is either a robo call  and the program is just dialing multi numbers over and over or there is someone using the automatic dialing system but not engaging on the other side; probably just putting time in, sleeping on the job. Call number seems to originate in Brigatine, NJ,  probably a call center of some sort, wonder what their game is?