My Samsung J7 has been great since 2018. Just 4 days ago, though, it wouldn’t turn on. Black screen with a little square box on left hand corner and a red line on the left side. It shows me 100% battery. After troubleshooting with a rep at Best Buy holding power and volume down, it came back on. Now it’s down again and won’t turn on. I need to get all the data off my phone! Help! I don’t want to do a reset factory wipe.