If this is what you’re experiencing then to get out of it you need to start a game in Casual Mode and then click on the Menu button in the top left and then choose Main Menu from those options which will then allow you to choose either option. Once that’s done you’ll have your choice of options whenever you start the game.
Hover your mouse over the “Play Now” button & wait for it to light up before clicking it. See if that helps. The Classic Blitz mode is the top button.
When Pogo initially rolled out the Casual Mode option it was set up as the default at that time as noted here:
http://www.badgehungry.com/2012/03/06/poppit-sprint-new-casual-mode/
If this is what you’re experiencing then to get out of it you need to start a game in Casual Mode and then click on the Menu button in the top left and then choose Main Menu from those options which will then allow you to choose either option. Once that’s done you’ll have your choice of options whenever you start the game.
I hope this helps and good luck!
– Tom