car issues

i have a 2005 cadillac cts and in feb of this year i took it into a cadillac dealership to have the rotors and pads replaced. immediately after they started making noise, i took the car back to the dealer 5 time since then and have all the documents showing this. twice they shaved my rotors and they claim they just dont know what else to do nor do they want to replace the parts to see if they where just defective. my car still makes noise and i dont want to go back again without legal advise about handling it. can you help please!