Sounds like a C&D.
Backstory:
A lot of companies out there do Not want their stuff being sold on eBay. Instead of going after eBay, eBay is saying "It's not our fault, go after them more directly, here is their information:"
A lot of companies do not want their items being sold on eBay because of the emergence of bootleg items of the same item that lowers the value and branding of items. In theory. So, if it can be bootlegged, it will be assumed it is bootlegged and none of which should be sold. This is good for the rest of the market, like distributors and retails, and the companies that own the property. Again, in theory, if nobody is selling used copies of something, people will be forced to pay whatever amount for a new retail item. This pertains very well to DVDs, because companies are selling them for such a low price, like Walmart selling them for $9 for DVDs that came out 2 months ago which they have to do because people are on eBay selling used copies for $5, legitimate or not, so Walmart can not charge $14.99 for 6 months after a DVD release like they used to back in 2007.
My Advice
Ignore it. Legal notices aren't sent via e-mail. A real attorney will collect some kind of evidence, contact eBay, get your information, then contact your ISP, get your actual information, and then send you a certified letter in the mail. Do not respond, and do not provide any information at all.