Justin Bieber is on the defense on Twitter after video has surfaced of him knocking down someone's camera while shopping with Selena Gomez at a 7-Eleven. OK! GALLERY: JUSTIN BIEBER FLIES SOLO ACROSS THE POND Justin just apologized for flipping off photographers on his birthday saying "he knows better" and now he was filmed knocking down a camera. But this time, the 17-year-old is not apologizing. "the lady in the store was paparazzi not a fan," Justin Tweeted today tweeted about the video below. "I would never mistreat my fans. ill ... Read More >>