How to solve a Soundcloud play/ pause bug?

After Soundcloud updated his API, I'm hitting a bug, I think. When you play a sound, you can pause it and after you paused, you can play the track again. But when you hit the button again, it doesn't pause the track. Only when you click 2 times more it will stop playing.

I can't find a solution for this, so does anyone know what I do wrong or is this a real bug inside the Soundcloud API?

The site is: www.mrooneh.com I use the following code to handle the play/pause button.

var isPlaying = false;

            $('.control').click(function(event) {
                event.preventDefault();

                var trackID = $(this).closest('li').attr('data-id');
                // console.log(trackID);

                if ( $(this).hasClass('play pause') ) {
                    // console.log('stop track');
                    isPlaying = false;
                    console.log('isPause')

                    $('#playlist li a').removeClass('pause');
                    $(this).addClass('play');
                } 

                else {
                    // console.log('pause/stop track');
                    isPlaying = true;
                    console.log('isPlaying')

                    $('#playlist li a').removeClass('pause');
                    $(this).addClass('pause');
                }

                if (!isPlaying) {
                    nowPlaying.pause();
                }


                // SC.stream('/tracks/' + trackID, function(sound) { 
                SC.stream('/tracks/' + trackID).then(function(player) { 
                    nowPlaying = player;

                    if (isPlaying) {
                        // console.log('play');
                        player.play();
                    } else {
                        // console.log('pause');
                        player.pause();
                    }

                });


            });

And is there a way to stop the track, after you go to another one instead of pause the track?

Thanks in advance.