It is no longer possible to buy the ticket at the ...

It is no longer possible to buy the ticket at the checkout and they ask you to buy it online in front of the entrance, creating endless files, people who are unable to purchase the ticket. I personally had Ip problems for having entered incorrect data, I called at the ticket office to ask for help at the ticket office (I had seen two people enter to get the reduction done which you cannot do online and if you do not insist at the entrance they tell you that you can't activate it) and they said it wasn't possible. The solution? I preferred to go away.