Several days ago I got an email from Spotify prompting me to download a new app from Google Play due to some security breach. So I went ahead and downloaded it and started to redownload all my old playlists. My Starred playlist, which I use as my primary library, cannot finish downloading due to insufficient space on my phone's internal storage. I removed the old version of Spotify on my phone from Google Play, but that didn't help. It appears that all the old downloaded files from the previous app are still stored on my device, taking up space and with no way to access them. 

I'd be surprised if I was the only person to have encountered this issue, and I'd like to know how to fix it.