Who called from 7409990055

It rang in but I didn't know the number so I didn't answer it.

I answered the phone but they hung up when I answered.

This number called the other night, 8 or 9 at night, and keeps calling.  They let it ring 2 times then hang up. Tried to call back last night and it said this number has been disconnected or is no longer in service.

Tonight there was nothing, they had already hung up, it didn't click or anything.