We've had our iPhone 5 since launch day and we got it as part of our contract with Orange (EE) and recently we've noticed that the mute switch becomes very stiff and we have to rock it back and forth a good few times for it to become usable again. We consider it a defect as we take good care of the phone and it's always in a case. Don't use the switch more than the average person. Who is responsible for attempting to repair it? Orange or Apple? How would we go about approaching either party?