Did you ask the seller if it is a legitimate version? How many positive feedbacks does this seller have? What is the positive feedback percentage?
You really have to be careful with software on eBay. Before you hand over your money, I'd weigh all of the above. Also, does the EULA for EWQLSO state that the samples are transferable. If not, you could be illegally purchasing a legitimate version.
By and large, I'd guess that over half of music software and sample sales on eBay are of illegitimate product (read: pirated/warez)
Unless he's an authorized dealer, he's *not allowed to resell the license* in other words he's not allowed to sell the library. STOP PAYMENT RIGHT AWAY!
Seriously, if you've paid by credit card, call the credit card company. Stop the check. Etc. You're absolutely within your rights at ebay and everywhere else, because it's illegal for the person to be selling the product.
My rule of thumb is to always ask a question to the seller. If I get a response, then that is a very good sign. I don't think you'll have a problem here. It looks legit. He's got over 4000+ feedback and 99+% positive. That's pretty damned good.