My star wars knights of the old republic game stopped working?

I went to play the game on the Xbox 360, and it wouldn't read my disc at all. So i went to see what was wrong with it, and there were scratches everywhere. I took it to a place to have it buffed, and it still wouldn't read it after that, then i tried a whole bunch of disc cleaning methods i found on the internet, and it wouldn't work after any of that. So i am wondering if i would be able to download the xbox version of the game and put it on a cd and play it that way, and if that is possible, could you give me instruction how to do so, and have the Xbox 360 read it. If none of that is possible, are there any alternatives of getting the game to work outside of buying another copy?