Who called from 4692065351

I got a call from 469-206-5351 and all I got was a loud beep in my ear.

I am getting calls from this number daily and cannot block it. 469-206-5351

This number has called several times and at first I did answer and all I heard was a LOUD beeping noise. Then I added it to my contacts list in order to block it and they were still able to reach me using the same number.
I've called back several times and all I get is a recording saying I cannot complete the number as dialed.

Who is this?  Why are they calling?  I get several calls a a day!