General contact
Use the public contact channel at https://www.sparkpond.com/contact/. Describe the route, browser and expected behaviour, but never attach a real confidential data file.
Security reports
Read /.well-known/security.txt and /security/ first. Provide a minimal synthetic reproduction and remove names, columns, values, screenshots and browser storage exports.
Accessibility feedback
Include the page, browser, assistive technology and failed interaction. A synthetic example is enough to investigate an import or grid issue.