This person is playing psychological games to manipulate my position. They aren't convinced that I understand their interests. They don't yet see that I want a contract that's fair for everyone. Don't let the other side goad you into making self-destructive demands or concessions that may undermine your ability to reach this goal. You are best positioned to change someone's mind after you have listened to that person.
People tend to close down and stick to their position until they feel heard.
Trying to convince someone of the strength of your case at a time when they are feeling unheard is like trying to paint a canvas that already has a brightly colored painting on it. The goal of active listening is for you to hear and understand other people - their words, thoughts, and feeling, and to let them know you've heard and understood them. When listening, resist the urge to defend yourself or to disprove what the other person is saying. Acknowledge their motivations, feelings, and point of view, even when you don't agree with what they are saying. I can tell you everything you've said.