Poor Quality Seats

I have a C200 which was purchased in August 2012 for my Dad. The vehicle has only done 38 816 km as it is used to fetch my children from school. When the car went in for it's service in August, I noticed that the stitching was giving up on the drivers seat. The Mercedes Benz dealership in Bryanston took photographs and sent it to Mercedes Benz HQ for review and approval of repairs. Mercedes Benz rejected the claim as the seats are only covered by a two year warranty for defect. I find this unacceptable as the vehicle shows no sign of excessive use or damage to the seat due to negligence by the driver and the mileage is low. One buys a Mercedes Benz because of the quality that is associated to the brand. In this instance, it is clear that the material used and quality of labour was inferior. I am really disappointed with Mercedes Benz as they have an obligation to acknowledge inferior quality and workmanship and should make amends by repairing the seat.