My iPhone 6 is no longer charging via USB or being recognised when I connect it to a pc. I have tried multiple lightning cables and multiple pc's (mac and windows). Also cleaned the lightning port with a toothpick to get rid of any dust. I'm guessing I have a faulty dock connector or a broken lightning pin inside the port. Does anyone know if this is a repair under warranty? I can't see any visible damage myself and I have always used certified lightning cables when charging..