I have a samsung Galaxy j7 sm-j701f/ds android version 9 pie. My phone keeps on locking itself and then the screen goes off and on many times. Then when I enter one hand mode , where I reduce the screen resolution, the small part of the screen will be the one going off and on while the rest of the screen remains on. And some of the settings in my phone are not working like the clock style. I think it's a software problem so at first I reset my phone and it started working just fine then after a few days it started doing this again. Please help.