Ask the c#nts why in hell you would choose to repair your own brand new car with non OEM parts if it's still under warranty, where the repair costs aren't even your concern?
Lawyer up...and if you can't do that, take someone with you to the meeting so they don't try and strong-arm you...hopefully someone you know in the auto industry.
Also mention if they don't sort it out you're taking a transcript of the meeting to the newspapers. For added fun, take your phone out and record the entire meeting.