I know that there's a new collection available, but I cannot find it in the app. What happened?

It may happen if you haven't updated the app to the latest version. Every new collection is added to the latest version available for our users.

Also, it might be helpful to force close Prequel and load it again (swipe up the app). 

You can check what has been added to each version in the "What's new" section on our page on the App Store or Google Play.