Unable to sync playlists to iPhone 5

[pm444]

For the past few days, I have been having problems with random tracks not synching to my iPhone 5. I have the Premium subscription, which until recently, has worked fine.

What happens is that the Spotify app literally gets hung up or stuck on a track. I have to force it to stop attempting to sync by turning off the "available offline" option for the playlist, but even then, the track that caused the problem will not play at all. It has no stop/start time showing, and while the pause/stop button shows, there's no music and it won't advance to the next track. If I quit the app entirely, then open it again, the track will momentarily display the stop/start time, but it will not play and the stop/start times disappear. 

I have Spotify on my MacBook, two iPhones, and an iPad, but I currently only have offline tracks on one iPhone. 

I had the same problem on my iPad 2, with the same tracks. So far, I have uninstalled the app, reset the iPhone, reinstalled the app, and the problem persisted.

Then I had Spotify support reset my devices, after which I uninstalled the app again, reset the iPhone, and resintalled the app. The problem is still there, and I haven't even reinstalled Spotify on my second iPhone or my iPad. So I have Spotify on my MacBook and one iPhone, and it still won't let me download tracks for offline listening.

I'm using iOS 6.1.4, and I have 26 GB of available free space on my iPhone 5. 

I have submitted a report to Spotify support, but my experience has been that they take a while to reply, so I'm hoping that someone here will have some suggestions. I have already spent way more time on this issue than any other tech problem I've dealt with in a long time, and I'm starting to get annoyed.

I'm also concerned because I have read other threads where iOS users report a similar problem which they say was never resolved.