Most NRA phone calls have one common denominator, money, but Hillman you are correct that we should use every opportunity we can to let it know our opinion concerning it's involvement in our right to keep and bear arms. Including when we don't want the NRA to meddle in them. As far as I'm concerned you did well.
Beyond money I'm not sure what the NRA's interest is in the U.N. gun ban initiatives are. The second amendment to the U.S. Constitution and the federal supreme court ruling that the right to keep and bear arms is an individual right, will surely limit the U.S. involvement in a world wide ban on personal firearms.