Losing all my offline music after starting spotify again

[Ibims]

Spotify: Version 7.5.0.1076 armV7
Phone: Samsung GT-I9100 Android 4.1.2

Changed my password.
After minor problems with Spotify I downloaded the new version 7.5.0

Now: I have to log in every time when I start Spotify, again and again.

But then my offline music is gone - completely. The albums and playlists are still there. But empty. I have to download everything new (in hours).
Next start - next login: everything is gone again.

Offline mode: off.

Thank you for your help!