Brake Pads Damaged

I took my car to have it checked because it was making noise where I press the break.I was then told that the one break is damaged and the other one is fine. I asked them how come because the car has done 42500km and its still under warranty.They said to me it means it's my driving.How can it be my driving....I have the same car and I do not have that problem!!!I was told that I need to pay R3000.00 to have my brake pads replaced and I'm refusing that.The car is still under warranty and how does my driving have to do with that.The dealer needs needs to replace them at their cost because its not my fault.The young gentlemen/ boy that works there has a very bad attitude. He needs to go for training on how to treat customers.If calls are recorded you are welcome to retrieve the call and listen to it.