Backspace and typing

I know lots of people have this issue but I do not know if I can resolve it or not. When I type backspace, it takes me back a letter instead of deleting the letter. I tried deleting the app and redox loading it but that didn't work. Also, on servers and multiplayer games, when I type, the screen above the keyboard goes black so I don't know what I am typing. If somebody knows anything about this please tell me.