Who called from 9712201048

Multiple calls in one day from number.  Automatically hangs up when I answer.

I am getting calls from this number which is disrupting my work or conference calls when I am working from home

I called the number back and it gave me the option (1) to opt out and be placed on the no call list. Guess what? I still get these @3###%^&&*!^&*% calls on my cell phone.