Is there an option to delete the thread completely (as they used their account to open the bitcointalk thread) or allocate the thread under our control or revert the page to the previous order or...? I can provide all documentation to prove that it's me.
Have you tried reporting that thread to moderator or making a new thread (like this one) as [ANN] to explain the situation? Not sure how that would go but if you point to this thread with "report to moderator" option, he'd probably be able to delete it.