eBay's policy used to be that only the trademark or copyright holder was able to file a complaint with eBay. Unfortunately, that policy has changed so that any third party can file a complaint based on no evidence at all.
DC Comics has a registered trademark for "Phantom Lady", so it seems safe to assume that DC filed a complaint regarding your reprints. I think if you pushed hard enough, eBay would give-up some more information about what happened to your listing.
Since the book itself is public domain, DC can't stop you from reprinting it, but you're going to have to find away around the trademark issue. The best idea I can suggest is an additional outer cover, to draw attention away from the "Phantom Lady" title, as well as to identify the book as being a reprint.