Looks like I got "Ingang Arena - Arena Vloer." Not sure what the difference is between that and just "Ingang Arena," but so long as I got the 'floor' ticket (which is what I wanted in the first place) I'm happy :)
That is weird yesterday (friday the 9th), i was half hour late when purchasing tickets. So at 9:30 i logged in and got myself arena tickets.
4 hours later i could even buy more (i checked for someone)
So you probably mean the normal sale today that was sold in 5 minutes ?!