When you call back this number there will be recorded voice mail that says please press 1 to redeem your $100 gift card.
After a couple of rings a customer service representative twill answer the phone thanking you to press 1.
He will ask you to confirm your name and address and say that you qualify for 2 $100 gift cards redeemable at stores like Walmart etc.
If you ask questions he will get irritable and accuse you of being rude and cutting him while he is talking.
If you tell him that customer service representative like himself should be more polite he will question you by saying " who told you I am customer service representative?"
And, yes they do give a missed call initially.
It seems like one of those IRS kind of scams which probably the police cannot do any thing about.
Annoying and scary at the same time.