You bought some tapes, you received something suspect, you questioned the seller about their legitimacy and they told you otherwise but you're still feeling burned - yet rather than fully discussing the matter directly with the person in hand and getting things worked out, you have to dilly-dally about it on here in vague terms? I can't see this problem being resolved between us helpless few, and the questions of ethics in underground business or whatever is redundant. Hell, maybe you should have asked more questions prior to buying them, or maybe you misread a listing description and you actually got what you paid for? It's hard to say as we're only going by what you've said, and we still don't know what mysterious label you're talking about to make a rational opinion on the matter. So really, you've got two options: either move on (shit happens, get over it), or get the matter resolved properly. If it's still not amicably dealt with - a refund, a return, whatever - spread the word about what they're doing and name them to dissuade others from hopefully falling foul of the issue.
A question for you: do you plan to buy from the same seller again in the future, knowing you may get a similar bum deal? That's a good starting point as to whether you are happy with their service or not.