I have a Samsung 9 which was fine until I put it to charge. At first while charging I got a flashing screen with a charge symbol in a circle in the middle of the screen. I tried to turn it on & nothing...thought maybe it was totally flat so continued to charge it overnight & still the same although the screen stopped flashing last night, I still get the charge in a circle symbol on charge & nothing when trying to turn on. I've tried holding the power button & sound buttons down together for 15-20 seconds, I've tried power & on buttons also...still nothing. Appreciate any help you may give, thank you.