Mera, where were you when my kid was selling magazine subscriptions for his middle school? Sounds like we could have made a killing.
Seriously though, it took me many years to realize that "no" doesn't mean "I dislike you" (or your vacuum cleaner, or your religion). It just means I don't want you to waste your valuable sales time on someone who ultimately will not be buying what you are selling. Saying "no" is saving them time and, really, doing them a favor. It frees them up to spend there time on someone who might actually buy what they are selling.