No longer own purchased games from store?

If you own the games, then log in with the account that was used to purchase the games, then goto settings - account - download history, and from there you should be able to download all the games you own including the ones that are no longer available
from the store.

It was delisted from the store, so it's no longer possible to purchase digitally. You would have had to own it prior to being delisted.

No, it's not true. Once a game is delisted from the store, it can no longer be purchased, unless the game is also available on disc. In the case of Snoopy Flying Ace, that game can no longer be purchased, as it was removed from the store as you know, and was not released on disc.

Thanks for your response,

So, this means that even if you buy an external code, it would not be valid because it has been delisted from the Store's Library and cannot be downloaded from the store's data base which is distinctly different from the database of those that have purchased or own the game prior to delisting. Any game that is delisted from the Xbox Store can no longer be purchased or redeemed if those purchases happened after the delisted date. If you purchased and redeemed before the game was delisted, you may need to contact support.

Best Regards,

Any game that has been delisted will no longer be able to download from the Xbox 360 store. If you haven't purchased the game, then your only option is to purchase a physical disc copy from your local or online game store. If you own the digital copy of the game, then you can download the game from your download history. Just goto settings - account - download history, scroll down to the game you want to play, and start the download.