Same thing happened to me a week or so ago. I didn't even let the guy get past the first sentence before I interrupted him, stating that they would not get a penny from me because of Bush's statement in support of the ban.
He tried to slip in a "but..." (presumably he was going to say "But we've passed gun industry lawsuit protection legislation"), but I wouldn't let him finish, completed my little speech, then hung up. Perhaps I should have listened to what he had to say, but I wasn't really interested in any excuses and/or justifications.
Then again, this guy was probably just a worker for a telemarketing company, and simply had a list of responses for various issues that their targets might bring up.
But if enough people respond similarly, surely this will work its way up to the GOP leadership.
--Mike