Spotify

I have playlists and albums I have saved to my phone on Spotify. I recently deleted all the music from my iTunes to save space and now solely use Spotify. The problem is when you save music to Spotify to listen offline it has to download using Wifi, now this is fine but for some silly reason, sometimes it decides it needs to download it again. So the anger comes when i have saved and album at home to listen to on my route to uni, then when i go to listen to it it says its not downloaded as it took off to make space for something else! I DIDNT ASK FOR THIS I AM OUTRAGED, so i end up listening to the same shitty playlst i am very bored of. ALSO it doesnt have a page for your downloaded music WHY NOT SILLY

unarticulate rant over...