My TV. has a black square in the middle of the screen and when I turn the volume up or down it goes away for a few seconds but comes right back. How do I fix it or get rid of it?

This is a simple fix, somhow you managed to turn on the closed caption, you simply need to go in to the menu and find closed captioning and turn it off, when this is on and set to the text it displays this black box you have