Maybe you haven't been ripped off but sold on a promise of sound excellence that just isn't there. I have a new '24 NX with the Levinson system. I have found it to be underwhelming. I have been disappointed at the lack of bass and power. I have decided to take my new car into a professional stereo installer to boost the amp, speakers and sub-woofer.
But if there is a technical issue that your dealership is balking at addressing call another dealership for help; it may equip you with info to present to your current dealer. Good luck!