Well, you're misunderstanding me now. I actually do fully understand the situation
No one is accusing you of anything. Quite the opposite. I can see very clearly (and so can DigitalNikos, I feel) that you're doing everything you can to get this resolved.
You will not need to give Nikos access to your license account that contains your personal details. I am just suggesting you add his forum name in the "Forum Users" section, that will just simply allow him to download resources.
Also, you will not be guilty of any copyright issues. The support case has been logged and both parties are happy to proceed. No one in their right mind would see any issue in you giving Nikos the files (by sending them by e-mail).
He's paid for it, and XenForo support are aware, so in this exceptional circumstance, I see no problems.
2nd hand licenses are bogus in my opinion. The company doesn't get any money, except future renewals. Just buy it from them.
All of this would of been solved. [/rant]
Not really very useful input.
XenForo offer the license transfer service at their discretion and I'm sure bogus has his reasons for selling as does Nikos for buying.
There's nothing bogus about them if all 3 parties involved are happy with the terms, which they clearly are.