I have the same issue as some people above: website shows availability (EZE-AMS) but when you book online it comes back with the seats are not available anymore message.
called 3 times now but agents can’t book it. They say it is a known IT problem that affects KL/AF flights and the KL /AF side is telling them they are not allowed to buy.
heard of several people that were able to get the booking through after trying different agents.