Local files that are not in the Spotify catalogue are not playable on my iPhone!

[Spotify-Me]

Hi there,

I transferred my local files to Spotify on my desktop and then into a playlist. However, only those songs available in the Spotify catalogue are playable on my iPhone. Those that are not in the Spotify catalogue are greyed out on my iPhone, and when I try to play them I get the following message:

"TRACK NOT SYNCED - IF YOU OWN THE TRACK, YOU CAN SYNC IT FROM YOUR COMPUTER"

I just want to know if this is a Spotify issue (i.e. you can't play local files on your iPhone if they are not in the Spotify catalogue) or if I am doing something wrong??

Thanks everyone!