I have a 1998 A4 Quattro. 67,000 miles. when i was driving it a couple of days ago i heard a bang and the engine stopped. the dealer says my timing belt didn't break, the oil pump works, there is oil in the car, but there was a MECHANICAL FAILURE. My engine seized up. I need a new engine. Cost = $11 grand. The car is not even worth that much!!! What should i do? isn't this a defect. I followed the maintainance schedule. how should i react, please help.