I just signed up for Spotify via Facebook. It seems to show me everything fine, artists, celebrities I can follow, apps, except for Facebook friends.
I have Spotify exempted from the only firewall I use. It just doesn't show any possible Followers from Facebook. It only says:
Facebook Friends on Spotify: There are no more people to show at this time.
I've signed out and signed back in several times, the problem is persisting.
A friend managed to link me to music, which linked me to her profile. Facebook friends are still not being shown.