Disagreeing and diffusing
You can get away with disagreeing with prospects as long as you show them the respect of really listening to what they have to say. Take into account when and if it makes sense to disagree.
Source: Colleen Stanley, sales trainer/author
You can diffuse an angry prospect by starting your answer to a question with the phrase, "You're making a legitimate point," or "I hear what you're saying," and really mean it.
Never underestimate how much prospects want to feel that they have been heard, and once you have given them that chance, they will hear you.