Hi Mike,
Thanks for sharing your experience, we understand your concern.
First of all, let us ensure you that the data is not lost. The spreadsheets are preserved as attachments in your Confluence pages:
To create backups, please refer to the following guides:
How to access "Attachments" in the new Confluence UI
Restore Deleted or Missing Tables
Upon investigations, our records shows that you’re using the free beta version, which was last updated in Nov 2021 (version 1.0.10). The beta version is provided as-is for evaluation/testing and isn’t covered by the same reliability guarantees as our stable production product. You can read more about beta version and its limitations here: https://docs.ricksoft-inc.com/excel-like-tables-for-confluence/beta-version-support
The issue described appears to be due to depreciated Atlassian API. For a supported, consistent experience and continued functionality, please move to the paid version. If you have less than 10 users, you may still use the paid version for free. Once again, rest assured, your data is safely stored within Atlassian, and updating to the latest version will automatically restore it.
If you need additional help, please reach out through our support portal: https://ricksoft-support.atlassian.net/servicedesk/customer/portal/33