You should be able to break the cloud link just by playing another source on it

 If you change your wifi password that will prevent him from repeating the trick if you ever let him in your home again.

I must admit I am amazed the steps you have already taken have not broken the link.

"Remove a speaker from Spotify Connect" doesn't really mean anything 

Unfortunately not John, this is spotify connect, once you have connected to a device it is then listed in your Spotify app see the picture below

 for example even if I am on 4g and WiFi off off on my phone I can still control it 

As John says, if you play a non-Spotify stream on the Sonos, that will ‘break’ any Spotify Connect sessions from anyone not on your local network. 

I have played local media from my phone but he still seems to have control when he wants to sadly 

Are there any other SONOS units in your system? If so, using a SONOS controller, make sure that no Rooms are playing Spotify. If you see “Started from Spotify”, play some different music in that room. This will break that remote Spotify connection.

Yes, that’s my understanding too - once the friend is no longer connected to the local WiFi network and a different source is played to the speaker, like playing music from Sonos Radio for example - that the friends Spotify account will not (cannot) reconnect to the speaker, unless you allow them back onto the local WiFi network.

They would otherwise need your Spotify account login credentials. 

Surely if this was possible (not being able to break the link) Spotify Connect would have disappeared in a storm of protest. It would be chaos, anarchy.

Other than getting on his phone and pressing this forget this device I don't know what to do. 

I have tried another source on my phone through the sonos app and then switched off WiFi and it was still listed as a device I could control in Spotify.  I only have a sonos one no other devices

How are you testing this? Playing another type of stream on your Sonos, when your friend is no longer on your WiFi, breaks their connection via Spotify Connect to your Sonos. It would have zero affect on your own device, as you are the system owner, and on your own WiFi. Unless you’re calling your friend and asking them to test, you will see/hear no change. 

Other than getting on his phone and pressing this forget this device I don't know what to do. 

 

I have tried another source on my phone through the sonos app and then switched off WiFi and it was still listed as a device I could control in Spotify.  I only have a sonos one no other devices

I think a local source should work to break the link, but try Internet radio.

You say it is listed as a device you.can play to. Did you.actually play through it?

I think he is coming off wifi and onto 4G

As I understand it, there is no way to visually see if someone has a ‘Spotify Connect’ session with your Sonos. But that is all Spotify’s software, and not Sonos’, so perhaps I’m missing something. 

I will bow out, and leave this to you, sir ;)

This will not be the case for your friend… All you need do is play something else to the speaker which will break your friends ‘remote’ session.

To regain access to the speaker, your friend would need to come back onto your WiFi network and start another Spotify ‘connect’ session. You can stop that by denying them access to your WiFi - either by charging the WiFi password, or blocking their device MAC address etc.

I would not remove the device from your Spotify account - you will need that for your own ‘Spotify’ connect playback. 

Sorry to clarify for everyone what I did and seems to have broken the link is:- 

1. Connected to the sonos private WiFi I setup for it 

2. I then played Internet radio, and an Mp3 from my phone using the sonos app 

3. I then came off wifi and on to 4g it no longer listed the device in spotify. 

Thank you everyone it was driving us insane let's hope tonight we don't get woken up! 

Sonos really do need to put some authentication in. 

Btw in-between we was using alexa to play our spotify playlists but it wasn't breaking the spotify connect session 

This is a Spotify issue. How can Sonos put authentication into something that doesn't use the Sonos system or the Sonos app?

To be fair we have an alexa and in the alexa it lists authorised devices even via Spotify and you can delete them