[randomkid88]

KEY_whatever Doesn't refer to the key of the keyboard, necessarily, like there isn't Key_a, Key_b, Key_c, etc. It refers to the mapping of that key to a control input of the game. For example, if someone wanted to use the backspace key as their jump key, then KEY_JUMP would be whenever they pressed backspace.

Long story short, KEY_BACKSPACE doesn't exist. For more info: https://sampwiki.blast.hk/wiki/GetPlayerKeys and scroll to the bottom