You will need to report to the company that manages the third-party service where your work has been republished, either on your own or through an official representative (like your lawyer).
If your work has been republished on a third-party site, you'll need to contact the management/support department of that site with proof that you hold the copyright.
It's possible the site may not respond by removing the work after you contact them, so please be sure to include as much proof as you can.
If your content has been republished on a site based outside of Japan, please use the template below to make your request for the content to be deleted.
I would like to inform you that your website features one or more works of mine that were reposted without consent.
Could you please take my work off your website as soon as possible? Thank you very much.
URL of the work(s) in question:
URL of the original work: