I had white scratches appear on my car soon after I purchased my 07 rx350-the dealer had done a great job detailing, but what happens is that wax will accumulate in rough spots or scratches and as wax hardens and gets rained on, it turns wet. So the scratches may only appear white because they are full of wax, not because they are that deep. These cars supposedly have an extra hard clear coat that is harder to scratch, but in my experience, it only makes it harder to remove scratches. If the body shop sanded parts of your car, a good body shop (not the people you went to) can use a finer wet sand procedure to buff it out. It sounds terrifying to fix a scratch with sandpaper, but my good friend is a body shop mechanic, and he's done this to repair clear coat imperfections on my cars in the past and the rx. As for your problems, its madness that the dealer has wiped their hands of the problem-I would be writing as many letters to as many people at lexus corporate as I could. You shouldn't be on the hook for any of this.