Hello! I'm a Premium user, I use Spotify both on my PC and my phone (HTC Explorer).

My problem is that when I download my playlists, some songs refuse to get downloaded. In one of my playlists I have 31 songs, but not all of them will play. 

They all work on the PC so these songs are available (they also work with wifi, but I need them to work in offline mode since I run out of free data traffic and have to pay my phone company extra for that), but for some reason they just refuse to download. I have rebooted my phone, reinstalled Spotify, removed playlists and downloaded the playlists again, added the unplayable songs in new playlists, but it still won't work.

How can I fix this?

These songs won't download and play: 

Artist / song

Naglfar / Way of the rope

Naglfar / Harvest

At the gates / Suicide Nation

Dimmu Borgir / Mourning Palace

Deathstars / The last ammunition

Deathstars / In vogue

Thank you! /Sara