Download purchased games that are not in the store anymore

Yes you can, if the game is not available on the ready to install tab, check out the wish list and download it.

If you're looking to download historical purchases, even if they are not for sale, you can still do so via

your Download History. You can also take a look at your purchases via your
Microsoft Account on your account page, which under Payments & Billing > Order History find the purchase in question, and then initiate the download, as long as you have that option turned on for your console.

You would redownload it from your purchase history.

1. Sign in to Xbox Live using the gamertag that you used when you originally purchased the content.
2. Go to settings and select Account.

1. Select Download History.
2. Browse your download history. If you want to download something again, select the item, and then select Download Again.

You can download the content as many times as you like, after you buy the game, if it does not appear to you in the ready to install list, then you may need to search the store, as well as check your order history if it appears in the order history. and
does not appear on your console, then you will need to contact support for an explanation of what happened.

Look through your purchase history and install from there.