MATVT Problem

[Dgethin2617]

Not sure if I can place this post here. I put MATVT on my Sony Tv, on the remote control the mute button was a bit small to change the scrolling and mouse pointer, so I stupidly I changed it to the select button. When I go to select something it changes the action of the cursor, consequently I can not revert it to the mute button. Hope someone can help me!