Dissapointed client

I recently bought a 2023 Renault Kiger at Morgan Nissan Upington. At 19000km I didnt think it would have any problem but the car makes an unpleasant symphonic noise when reversing. I took it back a week after I bought it and the dealership told me that the noise is standard with the year model and that it goes away after some time. I have the car for 2 months now and the noise is still there. Please advise on what I should do next.