From reading your post, I'm still not quite sure when your engine got blown. Are you saying that the car ran fine when you brought it in for maintenance?
Frankly, it sounds to me like they left a wrench or sup'm under the hood when they tried to move your car, or they hooked the battery up backwards. There is only 1 reason I can think of that the timing chains in V-6 should suddenly go out of timing - if they turned the engine by hand in a counter-clockwise direction for some reason. They should know not to do that. I'm assuming you have a V-6 because the 4 cylinder is a NON-interference engine. No such damage should happen on the 4 banger.
Have hubby run up to the shop with a digital camera, lift the hood & check the battery to make sure that the (-) battery terminal is toward the driver fender side of the car. If it's not, you know they messed up and now you have proof with a picture of it. Otherwise, they probably put a new serpantine belt on the car & turned the engine the wrong way by hand in order to assit in installation.
Even without proof, if the car was running fine & blew up when in the care of the shop THEY should owe YOU a new engine. You should pay nothing but for the work you reqested done. You should also get reimbursed for a rental while they work on your car.
In my opinion, based on the limited information in your post, they screwed up & are trying to get you to pay for it. Find yourself a good attorney.
