It's a SCAM, this is why be very careful when you answer these kind of calls, and never give them any of your personal information if they try to sell you something.
These numbers is a one time thing once they call you and you try calling them back it will tell you there number is no longer in service and next call will be another number even if you block them with the number that just called you, this is why be careful when giving them any kind of your information such like never give them your bank accounts numbers, credit card information and never give them your social security information if they ask.
The main thing to remember if you know anyone that are elderly they are the ones you need to watch over they will attack them people the most.