Yesterday during the xbox live log-in issue, I tried to play my world which has add-ons but they were not present for some reason.

When the log-in issues was fixed, it did not fix the add-on issue.

I had to reactivate all add-ons manually but I still lost all items, blocks and progress from the add-ons.

This, I feel, should not happen. The add-ons were downloaded. no?