Go here
http://resolutioncenter.ebay.ca/
and file as Item Not As Described.
The annoying thing is that you will probably have to return the remote to the seller with Confirmed Delivery. This can be expensive and yet will be necessary if the seller decides to be uncooperative.
So you have to decide whether the price is good enough to hold the batteries in with a bit of duct tape.
You have 45 days from purchase to file the dispute.
You have 60 days to leave feedback. The most effective feedback is calm and factual. Remember that your future sellers and possibly buyers will read it and form an opinion on you.
At the same time you will be asked to leave Detailed Seller Ratings. A normal transaction gets Five Stars. The lowest rating is One Star.
But learn from this. At a guess, the seller has a lot of second hand and repaired items and they are being packed by some poor sod in the warehouse. You got one of the dozens he had without the cover.
It is unusual that an item is better than its description.
Sweetie, we're crooks. If everything were right, we'd be in jail.-- Hoban Washburne