When the mystery boxes first appeared I had two possible prizes in the creatures box, Wiggops and Burns’ Dragon. I bought one, got Wiggops and the box disappeared without giving me a chance to get the dragon. Anyone know why? Or how to get the dragon?
There have been a few bugs with this update, you could try contacting EA to see if they can add it to your game:
The same happened to me! I have tried to contact EA three times and no solution for that! They are asking me screenshots of the missing item. Surreal.