Downloaded music disappears

[kunstmarshal]

Yet my playists remain downloaded. The same thing happened to me last week. I followed all the adivce on offer: cleared cache; formatted SD card; removed offline devices; reinstalled, and stared all over again only for the vast majority of my library to disappear. This is extremely frustrating.

The only common factor i've noticed is that on both occaisions i've been using spotify on my phone in a building I frequent that has wifi. Upon exiting the building, opening the app and trying to access my music, i find that all of it, barring the playlists i've downloaded, are suddenly gone. I've just now checked if too many offline devices are listed but no, just the one (and i only use one, ever). Is it possible that some bizarre networking/wifi error/gltich can cause this? Seems like a stretch. 

In any case, the usual 'fixes' don't seem to prevent the problem. The app didn't even appear to update, which i've also read can cause the same problem (what a ridiculous error to have on an app like Spotify). 

Please, any adivice is welcome. I love Spotify but for this one infuriating problem