Who called from 8782051021

Called 3 times on 4/20/2017, but left no message.

Called cell phone. Didn't recognize number so didn't answer. No message. Number now on call block list.

Caller disconnected after 11 seconds

Received call from this number and when I answered it, it was a computer generated voice asking me "can you hear me?" I hung up immediately.  Please be careful!

Thanks - I just got this call to my cell. But I never pick up numbers I don't know.
If anyone does they should answer with 'No' first or any nonsense word.
But never with a 'Yes'. Darn tooten be careful.
Going to go in and delete that nonsense right now...