Who called from 3345213574

I am on the 800 "do not call list" because I do not want these type calls.  I am not sure if that affects these calls or not, but I would like for it to stop.

This number calls often, sometimes 3-5 times aweek and no one is on the phone, when answered.

Also got a call from 334-521-3574 within 30 minutes of the Charlie call above. The caller also left no message.

I received a call that was identical to Robert and Charlie.  No message was left.

Again another call from 334-521-3574. Again, caller left no message but ID gives only the caller number.
Harassment...