Songs or Playlists do not show up and similar problems

[apolosisk]

Sometimes, I see the playlists or the songs dissapearing from my iOS spotify app. 

There is also another issue when I add songs "up to next". Sometimes, they are not queuing up! 

Also, once I saved 5-6 songs. When I got back the songs were not there. I reinstalled the app and the problems still remain. I do not get them everyday, but I do. 

Safety first : Is there a chance to get via APIs or spotify helpdesk, the songs that we saved? 

Secondly, why is this hapenning and how can I resolve this?