2008 Ford Taurus iS BROKEN KEY COVERED IN WARRANTY

I bought a 2008 Taurus X from Key Scales Ford in Leesburg, Fl in 2009 as a NEW vehicle.The key became unattached from the door lock clicker through no fault of mine. I put the key in the ignition turned it to start the car and the key fell apart.When I took it to the dealer he said I "MIGHT" have to pay for it because he doesnt think the key is covered under warranty. Is this true?