Unfortunately, when it comes to used parts and private sales it's a case of 'buyer beware'. As the buyer you need to be 100% sure what you are buying is in the condition you expect as your not buying from a shop, there is no warranty or money back guarantee. You can try and sue the seller if you can prove they had prior knowledge of any faults or defects that they didn't disclose before the sale, but with a private sale that's difficult to prove and is it really worth the hassle over a small amount of money.
I'm not defending anyone here, I never like to see anyone get ripped off, but in these situations the buyer also needs to take some responsibility. In this case requesting some clear photos of the item for sale from the seller before making your decision and agreeing to buy may have indicated these issues with the item and avoided this situation. One persons judgement of good condition could be another ones judgement of poor condition, taking the sellers word for it won't always give you what you want.
Publicly naming and shaming the seller really isn't the answer, if you do that your likely to burn your bridges and lose any chance of cooperation from the seller.
Did you sign for the item when it arrived? If not, the seller has no proof of delivery so I would file a PayPal dispute on the grounds that the item was not received and see where that get's you. If you do not get any final resolution from this then as Dylan suggested, the selling member may be banned from the site.