Recent (June/July 2016) marshmallow updates cause battery to not fully charge and accelerated dissipation even when it isn't being used. Battery metrics show Android Operating System using up to 50% of battery capacity. Have reflashed AND taken back to factory delivered status, still only goes to 65 to 80% as a full charge on slow charge and runs down very quickly. Any guidelines or feedback on this topic? Ready to switch to Apple, as also lost all contacts due to Samsung rep not verifying contacts successfully backed up to cloud before resetting to factory-delivered status. This grief is destroying me.