A group of Microsoft Products and technologies used for sharing and managing content, knowledge, and applications.
Not sure why the Msft agent is so confused about this - "classic" sites didn't necessarily have sites or teams in the url because generally they were created as subsites. So NONE of our intranet sites did until we switched to modern. In the SP admin center you can select classic sites from the filter drop down. Did you try that? Keep in mind only site collections will be shown - so if these sites were sub sites they won't display. In that case, try going to the "root" site (domain.sharepoint.com) and looking at subsites in site contents. Msft created this classic/modern mess - it would be nice if they paid a bit more attention to helping users sort through it.