There is a Report button on every listing.
Somewhere. It can be hard to find.
When you use it all you will see is a polite note from eBay thanking you for your Report. This is NOT the end of the investigation, but while eBay encourages members to police the site, it does not want to encourage vigilantes.
If you put the item on your Watch List, or the seller on your Favourite Sellers list, you can keep an eye on whether eBay believes there is enough of a problem to take action.
Some of the actions would not be visible, like higher fees, Defects on selling accounts, restrictions on the number and value of items offered, and a Hold on customer payments against the seller's performance.
Or the item or the seller may be ended abruptly. (NARU)
Generally, the Report button is more efffective than phone calls to bored clerks in Utah or the Philippines.