Official comment
Yes - this, and within 2 hours of you posting it... but we can't address licensing issues here, you'll need to file an inquiry ticket to have our rekordbox team resolve that for you.
And if the user said he'd sell you the license, then yes, he should have disabled it, but then it could be a case of your word against his - and if he decides to tell us he wasn't selling it, he is within his right to keep it and sell the DDJ separately.