Just bought TBS 3.5..no license key card inside so how do I register?????

Boy, do I need help! I just bought a sealed copy of Toon Boom Studio 3.5 from someone on Ebay, but when I opened it all it had inside was the disc and the installation guide…no product registration card, no license key card and the barcode label on the back was scratched out. I contacted the seller and he told me that the TBS was indeed new…he’d gotten it as a gift from his parents and that he sold it because he already’d bought a copy and did’nt need another. It’d never been opened or used and the reason that the barcode on the back was etched out is because his parents didn’t want his present to have the price printed on it…makes sense as we all do that, right? Let’s face it, when you buy somebody a “priceless heirloom” gift that actually cost you $5.95 at Walmart you certainly don’t want to advertise it! Anyway, this really puts me at a dilemma…does the software always have the license key insert card inside or is the missing barcode label the product registration number I need? If the answer to the former is no, then is the license key and all that a part of the disc when I actually install it? If not, is there ANY way for me to retrieve it or am I just gonna find myself shite outta luck? This is really REALLY important 'cos I’ve been waiting for nearly a year to finally buy this and now with TBS 4 coming out next month I’m gonna want to upgrade…please help!! BTW, the guy’s a legit seller with 100% positive feedback rating and has already offered to refund my purchase price if I can’t get this sucker to work. Again, paleeeeze help!
??? ??? ??? ??? ???