Game Pass has overwritten my previously purchased content

I'm having similar issues with digital content. Game Pass has stolen all my previously purchased content. So now I need to pay $15/month just to keep the games I already paid full price for? Wow. That's not in the FAQ.

Normally when using a 'season pass' to get all game content you need to launch the game to download the content with the games own content manager. The marketplace will not recognise that you've purchased the individual map packs. If this does not work and
you've previously downloaded the content you can find it in your 'my purchases' section in your profile.

Please assist in my question. I was previously able to purchase ..what has changed.

How can I confirm in which region a game pass was bought in.

Wr are very frustrated.

If you read the warnings before the migration it says this:

Previously purchased or downloaded content (for example, videos, games, and add-ons) cannot be downloaded again after migration. Previously purchased content is not refundable, and there is no guarantee that it will work after migration.

No, but I have previously purchased Xbox Game Pass.