Seconded. @jcranmer, lawsplainer links to a "RICO case statement" which reads a bit like a checklist. While the checklist makes it obvious why lawsplainer's examples aren't RICO, to my untrained eye the checklist seems to match the proposed claims against ebay fairly well. Could you cite the specific items for which you think the case is weakest?
For one thing, you couldn't sue Ebay itself. From the link above:
"Wait. Isn't the defendant the enterprise?
No. In fact the defendant can't be the same as the enterprise.
An enterprise is a legal entity or group of people. So, for instance, the Gambino Crime Family can be an enterprise, or Prenda Law. But the enterprise has to be different than the defendant for a RICO claim. Instead, the defendants have to be people and entities who run the enterprise."
https://popehat.com/wp-content/uploads/2016/06/Rico-Order.pd...