I've had something like this happen to me once or twice on eBay (one actually was a "Like new" steelbook, which turned out to be far from it).
If I don't know the seller from past purchase history, I'll open a case right away at eBay, describe the situation and request return for full refund. I've also used signed-for service to return the item, if I feel like I can't completely trust the seller. Bigger loss for me, but I'd rather make sure that I can get my money back for the item itself. Never failed so far.
A major disappointment to receive Iron Man in that condition, really sorry to see that picture!
Based on a few tens of steelbook purchases on eBay, most of the sellers (including private) seem to be doing a great job of packaging steelbooks. But of course you never know for sure what you'll get when dealing with a seller you haven't purchased from before and no feedback for steelbook sales...