Try to disable all the third-party plugins (including cache plugins), that does not come bundled with XStore https://xstore.helpscoutdocs.com/article/36-included-plugins , clear the cache of the browser, and check then. Maybe one of the additional plugins is the reason for the problem.
Let us know the result.
If the problem won’t be solved, provide temporary FTP access. If you do not know how to create FTP contact with your hosting provider, they will help you.
One standard license is valid only for 1 project. Running multiple projects on a single license is a copyright violation.