Convertible top not covered under warranty

[Sammy]

I just received a call from the dealer working on my vehicle and they are not going to cover the replacement of the convertible top that has a small crack starting to form. They are maintaining that the previous owners did not properly care for the window and seeing that I am the third owner I am simply SOL. The crack was not there when I purchased the vehicle two months ago and has only started to form in the last 2 weeks (yes, the weather has been quite nice the last 2 weeks). I have a 2002 S with 13k miles. Any advice? Am I SOL? Seems rough that despite the car still being covered under the manufacturers warranty I am limited due to how the previous owners took care of the vehicle.