Another ebay what to do?

Contact the seller. Don't get riled, just explain the problem & see what he has to say in response.
BTW, do you still have his email where he told you the part#? If so you might forward him a copy as a polite reminder that the problem is his. Ebay may be a lot of things but they do frown on misrepresentation.If he does not satisfy you quickly (1wk or less) file a claim with Ebay &/or Paypal.