Who called from 9194084002

i keep getting random phone calls during class, so i dont answer this is the 4th random #, all from different states.
how do i make id stop?

I just got one of these calls myself ...its a Charlotte, NC number. I answered they hung up.

I just got a call from the same number 919-408-4002  i answered it they hung up i call it back and they hung up twice

I just got the same call! They called and hung up on me. I have been getting calls like this for the past few days from numbers from all over the country.

Same experience, when I call back, its busy. How do we make it stop?