Warranty Claim Rejected

The harness under the passenger seat was trapped in the slot in the carpet leaving the hole exposed. A marble went into the hole leaving a bad rattle. I could not remove it myself due to the size of the hole. It was removed at my cost by the service department, Mercedes Benz, Centurion. After the removal of the object, I saw that the hole was now closed by a harness, that was not there initially. I requested this to be relooked at in terms of who is responsible for this payment. I insisted that this be a warranty claim, but was rejected after several attempts. There was a defect in the vehicle, in that the position of the harness was not correct and left the hole exposed for any small object to fall in. How can the customer be held responsible for the cost, and how can this be rejected as a warranty claim for a blatant flaw in terms of the position and installation standard of the harness. This leaves a bitter taste in one's mouth in terms of after sales care, especially in light of the very small cost impact it will have on Mercedes Benz to rightfully change this to a warranty claim which left the customer to pay for something that should not have happened from the start