My phone thinks my headphones are plugged in but they arent, how do i fix that?

Use a plastic or wooden toothpick and try to dislodge what ever is in the headset jack. Gently tapping the phone against the palm of your hand. If all else fails, make an appointment at the genius bar to have your device looked at.

Make a Genius Bar Reservation (or cancel an existing reservation)

http://www.apple.com/retail/geniusbar/

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