I am probably an eBay (seller) fool....

[Marc Anthony]

You're being too amenable to your zero feedback buyer. eBay is rife with fraud; it's really best to assume that a person without any reliable history, especially one buying electronics and claiming nonexistent problems, is up to no good. Now they're armed with your email, which is practically an admission that the drive is somehow dysfunctional. I worry that they'll get the charges reversed and, conveniently, "lose" your item in return shipping.