Reply to Traktor License issue

Sent my second replacement S2 back to native and got my 3rd back (4th one Im on now). That being said, this unit came in the original box and appeared to be a new unit with new software. I sold it shortly after having never entered or registered either hardware or software serial numbers.

Buyer received the unit and now is saying that the software serial comes up as being registered. This guy filed an eBay dispute immediately and upon getting in touch with him I realize he is a compete and total moron. He hadn't been to URL to download a full version on the software yet and hadn't made an account. I attempt to walk him through setup but I had the feeling he wasn't listening to a word I was saying.

My question here being is the software serial no good or is it registered in my account still or is this guy still just being an idiot?

Sorry for the mild rant and thank you for any help.