Board Thread:Love Live! School Idol Festival Lounge/@comment-37764117-20181209134251/@comment-11148831-20181213144531

You can send an email to info-lovelive@klab.com or use this contact form.

I'm not sure how helpful this will be since it is kind of outdated, but you can try visiting our own Love Live! School idol festival (JP Version) Account Recovery FAQs page.