I Just got a new reply from the support…
"Hi Mikael,
Thank you for your detailed follow-up and for sharing additional context about your experience. I completely understand the inconvenience this experience had brought you, especially given the expectations set during the migration process and the critical importance of your data.
Just a heads-up! When you switch from a Plus account to a ChatGPT Team workspace, your chat history doesn’t transfer automatically. If you didn’t export your chat history before migrating, unfortunately, it can’t be retrieved.
For future reference, you can export your chat history before making such transitions. If you need help with exporting data, see How do I export my ChatGPT history and data?."
So it was not to so much help. Nice that the instructions says:
"What will happen to my data if I merge my workspaces?
All of your existing chat history and GPTs from your Personal workspace will be moved to the Team workspace."
But i have found some other threads where it have been solved:
" I was able to downgrade from ChatGPT Teams to my ChatGPT Plus account with the assistance of customer support via the Chat on help.openai.com. This allowed me to retain all my Conversations and GPTs.
I was informed by customer support that should I wish to update to ChatGPT Teams again, I can currently export my Conversations manually from my ChatGPT Plus account and then use this export file to import it into my ChatGPT Teams account. However, this procedure does not allow for the export and import of GPTs from the ChatGPT Plus account.
I am very pleased to have my conversations restored, but I am reluctant to attempt the upgrade to ChatGPT Teams again. I intend to wait until the feature is available to integrate my conversations and GPTs as part of the standard merging process from Plus to Teams."
https://community.openai.com/t/switching-from-plus-to-team-all-chat-generations-gone-help-please/634417/19