Since June 2013 is not available anymore for free the item Punishment Stick to complete task to exit from Discipline Dungeon (a.k.a the jail).
I'm in jail, what should I do?
You have to purchase item from Power Up Store named "Punishment Stick + Wing" which worths 999 npoints. There no other way to exit.
Once you buy the item, exchange it at NPC[Warden]Cabal inside Discipline Dungeon to get your voucher for Dragon Wings and the Punishment Stick to complete task and exit.
Where I can purchase this item?
You can find it at Power Up Store, Section Power Up, page 7. Checkmark box and proceed to purchase.