I am posting this on behalf of a friend, as the forum will not allow them to post (probably part of the issues they are having).
They used to play years ago and are trying to come back and give it another go. They logged in and were asked to create a new Ubisoft account, which they did, and the man with the hammer came up to migrate the account, but they now have a level 1 account. I have searched on here an found various posts about migrating, and some say about ending up with a level 1 account, but none of them actually tell you how to sort it. Some posts say about deleting the level 1 account and then doing the migration again, but they can no longer login using the legacy login, presumably as it thinks it has migrated.
They have logged a ticket but after 3 days it still says "New" with no response.