Spotify keeps deleting my offline music on its own.

[Beetsteak]

As the title states the app is deleting my offline music on its own. On my previous phone (just upgraded the other day) I would ooccasionally find albums and artists that had their music "undownloaded" from my phone but still in my library. It wasn't too big of a deal as it was only a few songs here and there. As of upgrading the other day nothing I download has stayed on my phone for more than 10 minutes. I store my music on my sd card for more storage and formatted it last night to try and fix the problem but it didn't work. I also reinstalled Spotify and removed all traces of it from my new phone but that didn't work either.