Water leaking in!!!

Been noticing some water on the floorboard of the back seat, drivers side. Started investigating and found that it is coming from the top corner, near the window. Took it to the dealer and the service manager says that there is a gasket that is failing. Says he has done 4 or 5 of them Said he was going to try and warranty it, but truck has 60K. Called today and said he could only cover half. I would have to come up with 350$. I am waiting on monday to call the nissan consumer line. If the gasket is failing, shouldn't matter how many miles are on the truck, it should be covered. We also tried to get the regional service reps number and they told us he doesn't take calls from people trying to make claims. This was from the Clear Lake Nissan in Texas....Didn't buy the truck from them, and now i see why. Won't be getting any return business from me. This is the second problem we have had with them.