For the most part my Verizon iPhone is awesome. I have had a problem with it for the past few days. Occasionally while on a call the earpiece shuts off so the person I'm talking to can hear me but I cannot hear them. It's as if they put me on mute. This has happened multiple times with multiple people. It's obviously defective. In order to exchange do I have to go to the genius bar or can I go to any sales person for a return / exchange since it's within 30 days? I bought the phone online directly from apple.