95 lumina steering

I just had new front steering seat mounts installed. Since the new seat mounts were installed I have developed a creaking noise every time that you turn the wheel. It seems to be traveling up the colume. The shop that did the work say that it is the rack and pinion making the noise. They said it has to be replaced at a cost of $600. Does anyone know why replaceing the mounts would have caused the rack and pinion to start making a creaking knows.
Thanks guys

Please help

Try a different shop.