Local Files are not playing on my iPhone 5 unless i'm connected to my wifi

[MontyChristos]

Hello, I have trawled through some of these threads but found no answers. 

Ok.. So spotify on my iphone 5 will not play any tracks that I also have in my local files. They appear on my phone but the timer bar below the album art work won't start playing unless bizarrely i am connect to my wifi. All the local files mixed in to my playlists will play fine on my Macbook but not on my phone. 

Why is it doing this? Some of the local files I own are on spotify and they won't play either. So it seems if I deleted my local files it would play them but I need this solved as I want to listen to Led Zepplin, The Beatles and all that.

These playlists are all marked offline so i'm at least not being that stupid.