All this interactivity is achieved by building the html in the client instead of on the server. As the users interact with the webpage, logic on the page is morphing the very structure of the page. This allows you to refresh part of a page without reloading the rest of the page, or rearrange data without making any requests to the server.
They left you with a new set of problems.
It's ok, you have options.
You're not the first person to run into this problem. In general, there are two ways around it: duplicate some code or run a headless browser.
Regardless of the technology, if you are focused on making the best experience possible for your users, then you're on the right track. In this particular case, that may mean you'll need to figure out how to fix this SEO problem. Don't worry. The two options above will both work. If you have any questions, don't hesitate to ask. Just email firstname.lastname@example.org. I'll be glad to point you in the right direction whether you want to use our service or not.