You could take the middle road and leave a neutral and when you leave the stars give them 3 stars for item description..
Here is the return process in case you did not already know it.
What to do if you don't receive an item or it doesn't match the seller's description
http://pages.ebay.ca/help/buy/item-not-received.html
Returning an item
If you'd like a full refund, you'll generally be required to return an item. Here are some things to keep in mind:
Don't send an item back unless the seller or eBay asks you to.
Package the item carefully and securely with all parts. The seller must receive the item in the same condition as you received it.
When you send the item, you'll need to include tracking information. For items worth $250.00 or more, signature confirmation is required.