I have/had an 99 QX4 with 205k miles on her. She ran like a queen until she started to squeal a little bit. After changing all the belts and pulleys, it was determined that I needed to change the Harmonic Balancer. Well I took it to the dealership and it took them a couple of days to finally get it off and replace it. I went to pick up my car and no less than 30 miles later my fan and the metal bracket connecting the fan to the pulley (for a lack of better term) popped off and destroyed all my belts and trashed my radiator. Obviously my car overheated plus it died since it cut off the belt powering the alternator. Well I called the dealership and they are trying t say it was because of my cars age that this happened and are denying any fault. They said they did not touch my fan even though they changed the fan belt because they claimed it was the wrong size. looking at the pictures, my question is do you believe this was a random stroke of bad luck or the dealership forgot to cross their T's and dot their I's before giving me my car back. What should I do?

I very upset because she was a great car that was good to me and I sure I could have got her up to 300k. This is the 1st time she has ever died on me