Went to the song festival yesterday. We had ticket...

Went to the song festival yesterday. We had tickets for Ring 2. Once there, a lady is waiting for us with the good news that we are getting tickets for Ring 1. When we go to Ring 1 with those tickets, those seats turn out to be covered with a black sail and not available. A few minutes before the start we are told that we can no longer get seats due to an error and that there are only standing places left. Whether the fault was with Ziggo Dome or Ticketmaster I don't know, but you could expect more professionalism from such an organization.