Here's what the Android programmer says about that: to help add the DLC you can download an external file management app like Amaze File Manager (play.google.com/store/apps/details?id=com.amaze.filemanager) or to connect your phone to a computer to move/update the files.
You'll need to redownload and install the base game and any other DLCs you own to have them be up-to-date as well. I'm sorry for the trouble!