Is there a setup menu in there somewhere? There may be a setting for the screen orientation. It may not be in your manual, maybe some online research would give you a direction to go in (sorry about the pun). Of course, you've already reset the control by unplugging it for a while.
There is a way to flip it back. You need to hold the OK button, while holding it down unplug power from the back of the stove, keep holding the button down and plug the stove back in. Keep OK pressed down until screen lights back up. It will be right side up for you.