Please help! Brand new iPhone, camera and flash out of sync?

Hey so I bought this iPhone 6 a few days ago seemingly brand new, other than the fact it had no touch id. I didn't notice until today but when the camera takes a photo with the flash on, the photo comes out black and sometimes depending on what lighting the photo was taken in would only show a feint outline of the subject I was photographing. The flash works fine in video. I googled and found a similar problem with an iphone 5 and it said that the flash and camera were out of sync but I don't know whats going on. I have tried restarting and I even factory reset the phone but nothing changed. It still has a 12 month warrenty on it so should I ask for a refund/replacement? Thanks in advance :)