Classic games deleted without notice and unable to recover

Give this a try

Hide or unhide items in Ready to Install

When you uninstall a game or app, we move it to the Ready to install tab, which appears at the top of My games & apps.

To keep your Ready to install list pared to the items you’re most likely to use again, hide the ones you don’t want to see:

1. In Ready to install, highlight a game or app.
2. Press the Menu button on your controller.
3. Select Hide from list.

To unhide items, go to My games & apps, press and hold the left stick on your controller, and then press the Xbutton. To re-hide an item, repeat these steps.

To reinstall a hidden game or app, simply unhide it and then install from Ready to install. Or, you can download and install it again from the Microsoft Store.

There could be also some sort licensing problem. That sometimes causes games to be removed/delisted either permanently or temporarily often times without notice or refund. Purely because
of the fact that when you agree to purchase something you also agree to like 8 million other things and the random removal of licensing from platforms is always one of those things. That's sometimes the case for why random games go missing, its the publisher...
not Microsoft's fault.

Regardless of whether or not that's the case you should always follow up with the official support about it because they're actually able to get into your account and stuff to see what the problem is.

https://support.xbox.com/en-US/contact-us

Most likely they are still on your account. The purchase history on xbox.com is not always 100% accurate for 360 content if it even shows them at all. You would need to check your history on a 360 console for the most accurate list.

You'll have a better chance if you present the emails received upon purchasing.

Do a search within your microsoft/xbox email account: "We're sending you this message to confirm that you have recently purchased the following items: "

or search by sender: *** Die E-Mail-Adresse wurde aus Datenschutzgründen entfernt. ***

I hope this helps as well

are you entering your email and password correctly when you go to recover it? worst case you can always plug in a USB flash drive on your friends 360 and transfer your account to that drive and then plug it in yours when you get home.