OTW, I think you've already done the right things. Even if IHQ can't do anything, it is something that they probably would like to know. And it was exactle right to inform ebay. They are a business nad they need to know if things like that happen.
By the way, if you don't mind my asking, what's your ebay username? You have probably bid against my mom many times!! You wouldn't believe how many time people have emailed her asking if she is an AGD. She has to explain, no, she isn't, but her daughter is! People always apologize, but I explained to her that things like pins shouldn't belong to non-AGDs, so that's why people ask. So now she sometimes strikes up conversations with the people who email her! Who does that remind you of??!!