Hello,
01. You can deactivate the license for the old domain via the settings of your account on our website.
Let me know the result.
02. Regarding the demo import issue, please try to deactivate the third-party plugins and import the demo again.
Note that our dummy content works only on a fresh installation. If you have some content already, it will conflict with your existing posts, and most of the content will not be imported correctly.
If the issue remains, try to increase the “PHP Max Input Vars” parameter to 10000 or higher in your PHP configuration and import the demo again.
If the issue still remains, let me know which demo you want to import so I will check and give you a possible solution.
Best Regards