Called the 941-203-4045 number back and received a recorded message identifying them as the National Rifle Association.  Pressed "1" for more information and was immediately prompted for the telephone number I wish to have removed from their call list.  Entered my telephone number and then was informed that by Federal law they have 30 days to act upon my request, but that they would attempt to remove my number in the next 1 to 2 days.