Org and channels not accessible after upgrade to microsoft 365 basic

Hello there,

We created an org in the free version of teams. I am the creator of the org and some channels under the org. Since things were very slow (24 hours addition of users to channels or the org), I subscribed to the basic microsoft online subscription.

Now, when I try to log into the org - I'm unable to do it. It's as if Teams is treating me as a completely new/different user than before. The org in Teams has other owners. When those owners invite me to the org, I still cannot see the channels and things I created before.

I understand that I'm not somehow under active directory, and that I wasn't before, but -

Is there a way to undo the microsoft registration (we already cancelled the subscription after it messed the org up)? Other users and co-owners of the org can still see the channels and contents, but I need to be able to do the same and basically restore all that I lost during the transition to the new subscription.

Please help?

Thank you.