Nissan refusal to repair faulty Ignition.

I purchased a New Nissan NP300 for cash in 2017. Before my first service I notified the dealership that my key was faulty . They refused to assist me so I contacted Nissan HQ in JHB without any joy . Wear and tear is what the verdict is ...I must pay. I'm on my 5th service now and my second Key is faulty . Help me because Nissan does not want to .