Or use Audible credits for the audio-book companion to Kindle books? For that matter, is there any device I can access the audio companions I've purchased for

Or use Audible credits for the audio-book companion to Kindle books? For that matter, is there any device I can access the audio companions I've purchased for my books other than the mobile phone Kindle apps? Can't do it on the PC app, the web app, on my actual Kindle, or my Fire tablet.