National Police and Sheriff's Coalition PAC review: Make this stop!!!

Have sent money to this organization on a couple of occasions. I'm wondering if this is a legitimate business/charity? They seem intent on making several harassing phone calls/robo calls, trying to extort more money from me. Have emailed them and am to the point of a nervous breakdown with the daily phone calls! Moreover, the calls have become more than once a day! Have reported to The F.C.C. as well. What more can I do to make it stop?