Today I found that calling Play via dbus when the music is paused has no effect at all:
qdbus org.mpris.MediaPlayer2.spotify /org/mpris/MediaPlayer2 org.mpris.MediaPlayer2.Player.Play
As a workaround, you can call PlayPause (but, if the music was already playing, this will pause it instead! so for the workaround to work you have to check first if it is playing or not)
qdbus org.mpris.MediaPlayer2.spotify /org/mpris/MediaPlayer2 org.mpris.MediaPlayer2.Player.PlayPause
I hope you will fix it, it seems easy to solve :)
Thanks!