keeps calling me and hangs up when i answer.

Allegedly it is some company that helps people find gov grants for school etc., but their rapid-fire calling approach -- virtually harassment -- and leaving no phone messages -- makes one assume they are not very reputable.
I understand sometimes you might get five or ten seconds of "dead air" before the caller starts talking so wait a minute before hanging up.
Once you get a human, be polite and formally request they stop calling if you are not interested in whatever it is they do.

PLEASE REMOVE MY PHONE NUMBER FROM YOUR CALLING LIST.. I AM NOT INTERESTED IN ANY SERVICE YOUR COMPANY PROVIDES.. THANK YOU

This number has called my boyfriend 12 times today and everytime I answer his phone they hang up on me as well. They have been calling for the past 2 weeks now. I called this number back and they are a grant business but didnt take time to listen to what they had to say..told them to take us off of their list. It was a live person so this should take care of it...hopefully!!

This company calls me from one to three times per day, wasting my expensive minutes!  I've filed multiple reports with the Do Not Call web site, but nothing is being done.