Game wont reinstall

I got call of duty cold war with the content packs 1 - 4 and the land sea and air pack on my Xbox one s (its was around £100 if I remember correctly), everything worked fine. The one s was getting old so I upgraded to the one x. I then transferred all my games but after fully installing the game and trying to play it, cold war wouldn't open and Xbox said it needed to be bought again. I tried lots of things but nothing worked, I then did the worst move possible and uninstalled it hoping to reinstall it, but because I am on a one x it wants me to buy the next gen version and isn't giving me any option to reinstall the game version I had bought on the one s. Does anyone know how I can reinstall the game as I now know how to fix the game wont open issue but I don't have the game installed because of my attempt to reinstall. I have the game still on the one s, so if there's a way to transfer it, but I just cant install the cold war version I own. I also don't want to rebuy and lose all my packs as they cost a lot of money.

:)