Well, by the OP's own statements, the dealer has agreed to fix the problem multiple times under the extended warranty good only at their dealership. The OP has attempted to circumvent them by going to someone else and still trying to get the dealer to pay for the repair that they haven't been given the opportunity to look at.
The dealer is justifiably frustrated with the OP's attempt to micromanage something he knows very little about. The dealer has apparently bent over backwards trying to fix the OP's problem and are frustrated with the OP. If this were me, I would tell the OP to bring it in to have it looked at or go pound sand!
Keith