my suggestion

still a lot of details unclear.

first, any damages? if only the rack was broken or disfigured, then simply return it and get ur money back. any damage on ur car? if so, call the service number and make a complainment. remember, keep the phone bill as a potential evidence. if the situation is worse, talk to a lawyer.

second, make sure you follow every step shown on instruction. you have to talk to someone like a mechnic or at least a handyman working for a car dealer. just ask them whether rack falling happened before in ur area and if so, how often. just check ur chance to win the case.

if u believe there is nothing wrong on ur part then talk to a lawyer directly.