In every URL line under any product, you will find the edit, report, and delete buttons. If you see any incorrect price or stock information or a URL isn't updated after the initial 24 hours, you can use the Report URL button to inform us. It's totally enough to report just one example from one site, then the site's all URLs will be checked.
Google Shopping channel-based monitoring prices are fetched from Google Shopping directly. If you believe there is a false price or stock information on channel-based results please contact us via live chat.
Here is also a quick video about how to report a broken URL: