You're right, Sableman doesn't understand. He's a lawyer, not an alarm guy. All he knows is what Brink's tells him. Brink's is the one who's making stuff up. Get pissed at them.
Getting at the truth is what the discovery phase of litigation is all about. Both sides gather evidence, expose misconceptions or outright lies, and either come to an agreement or present their cases at trial for a judge or jury to decide. The lawyers do battle. If both sides could agree on everything within a couple of weeks, there wouldn't be any need for a lawsuit.
At this stage, it's normal for each side to believe the other guy is being an unreasonable bastard. The problem is, Jim doesn't have a lawyer, and hasn't followed the rules of litigation, and therefore he probably won't get the opportunity to expose the truth. That's a crying shame.