How Do I Forget or Delete An Available Device?

[WendySFO]

A week ago I linked to my friend's Heos sound system.  I will never need to do so again, but Heos still shows up all the time as an available device in my Spotify app.  I have tried signing out everywhere, but that did not get rid of this device.  I have tried deleting all offline devices, but since this device is "available", it is not offline and cannot be deleted.  

Can anyone help me solve this?  Do I need to call my friend and ask her to sign in on her own system?  That seems silly, plus she doesn't even use Spotify.

Advice would be greatly appreciated.  Thanks!

[sanjayrath]

We cannot find which devices are regostered. We cannot delete devices. We do not even know which is these mobiles we have thrown away. We cannot even buy higher 10 device version. Terrible weakness in Spotify