c-139 cell dispaly is black

It is easy on this model phone to accidentally turn off the backlight completely while changing the settings, making it impossible to use the phone or change the setting back. The "official" instructions say to "Press M > Settings > Other Settings > Initial Setup > Backlight" but you can't do this if you can't see the display. You MAY be able to shine a bright light on the screen and read the screen enough to do this, but not if it is badly scratched. The provider does not have instructions to correct this. From the "home" or "power-on" screen, press the middle round button. Although you can't see it, the screen says "Prepaid". Press the "Up Arrow" 4 times. (The screen says "Settings".) You could also press the "Down Arrow 8 times. Press the left "dot" (the button directly under the left side of the screen). The screen will go to the "Phone Status" option in "Settings". Press the "Down Arrow" 3 times. The phone will say "Other Settings". (You could also press the "UP Arrow" 1 time.) Press the left dot on "Other Settings". The phone will be on "Personalize" in "Other Settings". Press the down arrow 1 time. The phone will be on "Initial Setup" in "Other Settings". Press the "Left Dot" on "Initial Settings". The phone will go to "Time and Date" in "Initial Settings". Press the "Down Arrow" 3 times to go to "Backlight". Press the "Left Dot" on "Backlight". The phone will be at selection "Off" in "Backlight". (Pressing the "Left Dot" at this point on a working phone will create this problem by turning the backlight off permanently.) Press the "Down Arrow" 3 times to go to" 20 seconds". (You could also press the "Up Arrow" one time.) Press the "Left Dot" (Select) on "20 Seconds". The backlight should come back on if the provider has not changed the menus too much. What maniac designed this system?