CA bought car but wrecked!

[usmc123]

I bought a 02 Jaguar about 5 months ago. I just went yesterday to try to trade it in and they told me that my $15K car is only worth $3K now due to it being in a wreck. I was never told of this before i bought it. I asked the dealer if there was anything wrong with the car and he assured me that the car was fine. In fact he was so confident in the car that I wouldn't need GAP insurance or an extended warranty. I don't know what to do now. What should I do? I am stationed at MCAS Miramar in San Diego, CA.