I have an even messier problem. I got UNiDAYS student account just before I got my MacBook. But I didn't it verified, so it was not a full account, and couldn't be redeemed anywhere. After I got my MacBook, I subbed to Spotify Student (Using SheerID I think) and that wasn't an issue. But recently I switched to Apple Music Student, and used the same institute ID for another UNiDAYS account which had my Apple ID (@icloud.com) as the main account, since the before account (note: it was not an apple ID, @gmail.com) got the student email too.
Now the issue is that, sometime after Apple Music subscription, the I apparently verified the @gmail.com UNiDAYS account, so I got kicked out of Apple Music Student. I panicked and 'created' a UNiDAYS account for my Apple ID (@icloud.com), without just changing the UNiDAYS account email to the Apple ID one. And I also 'deleted' the @gmail.com UNiDAYS account. It takes UNiDAYS 30 DAYS TO DELETE MY ACCOUNT!! Until then, I cant add my institute ID to my @icloud.com UNiDAYS account (because since it was used somewhere else, and that account was deleted, it shows an error)
Now I have to wait for a month for the account deletion, and add the institute ID to my apple ID in UNiDAYS and subscribe to Apple Music again.
Bummers.
But since now Apple uses SheerID and not UNiDAYS, it is an even messier problem, because I did not mess with anything else with the @gmail.com account let alone SheerID, and it still shows me I did something wrong.
Attachment: Apple Music student verification through App Store, MacOS Sonoma 14.5