You can unsubscribe from Apple Music by following the step mentioned in this article:
View, change, or cancel your subscriptions - Apple Support
You can also try to recover your Apple ID information:
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Your Apple ID is the account that you use to sign in to all Apple services. Usually, your Apple ID is your email address. If you forget your Apple ID, we can help you find it.
If you forget your password, you can reset it from your device or your Apple ID account page.
If you can't find your Apple ID or reset your password, you'll lose access to your account and might be unable to use or reactivate your device. To help prevent this, visit your Apple ID account page periodically to review and update your account information.
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copied from: Activation Lock for iPhone, iPad, and iPod touch - Apple Support