Hello,
Sorry for the delay in answering.
It is strange.
Try to disable all the third-party plugins (including cache plugins), that do 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 a reason for problems.
If it is not the plugin’s fault also, we would recommend you change your hosting provider. We can not see any problem with the purchase code or from our side.
How did you create the site to its current state without theme activation?
Regards