Thanks for posting about this here in the Community!
Just to confirm, is your Spotify account created through Facebook?
If so, due to technical issues, it won't be possible to change the email address registered on Spotify this way. This would explain what happened here.
If you'd like, you can always sign up for a new account through Spotify directly and then connect your Facebook profile to it. To close your original account and have your music to your new account, just follow the steps inthis Spotify Answer. Don't forget to cancel any subscriptions you have on your original account - just follow the steps here.
Let us know how you get on! We'll be right here if you need more help.
Have a lovely day 🙂
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