Hard to say without seeing pictures of the cases and knowing what exactly is wrong with them.
Cost is gonna be whatever shop rate is. Probably 80 bucks a hour.
So it really depends on how much time will be needed to fix them as far as cost is concerned.
I had some bad cases that needed 600 bucks worth of work. I decided to pay 600 bucks for some brand new Ultima Cases.
As far as who to recommend in CA, I have no idea.