Apple ID verification messages

Hi Apple Community,

I have been getting the "Apple ID verification - Enter the password for _____@domain.com in Settings" which has been pinging my Apple Watch and iPhone every 30 mins all day today (very annoying).

The thing is, the two Apple ID's it's asking for are not mine! I think what has happened is 10 years ago (when I got with my partner), I downloaded some songs (from her ex) which of course didn't play on my computer, but I never deleted them - how do you fine them easily in a library of thousands of songs?

All of a sudden, I'm getting this annoying messages and can't for the life of me find a way to get rid of them! When I click the message and go into Settings - all it gives me is to add the password, and then goes on the "forget password" path which I of course don't want to go down because it's not my email address/Apple ID!

How can I get rid of it? How can I find the songs/media that belong to the other accounts so I can delete them and remove the need for the password so I can have some peace?!

Any help is greatly appreciated!

Thanks,

Jezza

Both iPhone 11 Pro and Apple Watch are on the latest OS. Not getting the Apple ID verification annoying messages on my MacBook Pro which I only updated to Catalina this afternoon.