You can probably turn off the CC manually from the front panel.
According to the manual, you can access the adjustment menus by pressing the VOL+ and VOL- simultaneously.
And another thought....
I assume that this TV doesn't have a built-in ATSC or QAM tuner, so therefore you are using an outboard box (cable/satellite?). Check that CC isn't enabled on the box. It may not be the TV.
If you can’t explain it simply, you don’t understand it well enough – Albert Einstein
If you haven't already done so, dig around in the menu and see if there is a reset/default function (probably within a system sub-menu). Also look for a small hole on the front panel for a recessed reset button, maybe on the rear but be careful back there.
And did you try Ratman's access method? Maybe it provides a different set of menu functions.