Razer Tiamat 7.1 V2 - No audio

Everything is powered, the headset shows lighting and the volume indicator also. All are rotating colors, as you'd expect. The Controller (?) for the tiamat has the middle button lit green, and nothing else. none of the buttons respond, unless you 'mute' the audio. at which point you can "turn on" the 7.1 and mute the mic. i've tried unplugging everything for a few mins, and plugging everything back in. i've confirmed it as my default speaker. and i've also tried changing different headset / speaker and the other 2 work fine. any help would be appreciated.