How to unlock content in Magic Origins

Magic Origins has a story mode where you play as a planeswalker and earn some gold.

I played through the whole first story (all battles, all skill matches) and the other planeswalkers are still locked.

What do I need to do to access the other four?

I bought the packs as suggested, I replayed that last guy Iora game, I logged in and off. If there was some hint, I missed it.
I saw people on the Internet lament about the game crashing while playing as Chandra, so I'm pretty sure it's not something that would be unlocked later.