Hello,
Thanks for reaching out to us. 
Please, check the documentation: https://www.joomshaper.com/documentation/helix-framework/advanced#import-and-export
If you think issues still persists, Could you please share temporary administrator access to your Joomla backend? You can provide the credentials securely in the hidden content section. Also, please take a full backup of your site before we make any changes.
Once I have access, I’ll investigate further and see what’s causing the issue. Let me know once you’ve shared the details!
Best Regards,