Who called from 6239589851

Code came up as ' test code' ... I was on another line so did not answer

Hung up when call went to voicemail.

I think that when you get a call without a voice, they are checking to see if the number is valid. If I am around when those calls come in, I pickup the phone and immediately hang it up. My amount of calls has dropped by 50%. They take the valid numbers and sell the list.