Can you please assist me with the issue? I recently deleted the site where the license was registered. The site has been completely uninstalled, and the addon domain, along with any databases, has been removed from my hosting account. However, when I attempted to use the purchase code on a new site, it stated that the code is already in use. Can you help me, please?
If the website is same mean same website but different domain then old license you can use but if the website is different mean different end product then author may require a new license.
To use purchase code (license) again which already used for any website (mean license already registered) you have to unregister/deactivate the license from the old domain/website. you can not use the same purchase code (license) for more than 1 website.
If you don’t have access of old website wp-admin then you have to contact theme/plugin author and request them to unregister/deactivate the theme license from the old domain/website.
contact the Author and let them know How to Contact your purchased theme/plugin Author, the author will be happy to assist you within their scope.