I'm sorry, I got the code for free from Gamivo, where I wouldn't shop normally, like in most keyshops, so it seems my suspicions were correct.
Unfortunately it seems like official distribution ended and the only place I can find is G2A, where I would also rather not shop, as they are a keyshops and most keys are probably from Gamivo, so I think it will be best if you just mark the giveaway as 'not received'.