Connecting to a Specific Sonos speaker when someone else is/was connected

Please can someone help me before I lose my sanity. My son was connected to one of Sonos speakers last night.  He is out of the house currently and I cannot connect to the same speaker. When I go in the Sonos app and go to the speaker, it shows as my son’s spotify connected, but not playing. When I hit play it starts playing his Spotify on the speaker, even though he is listening to Spotify on his own phone outside the house. That pauses his spotify on his phone and starts playing it through the speaker in the house. He can play it from his phone and take it back to his phone, but either way I still cannot connect to the speaker in the house.  How do I kick someone’s connection off?  It’s ridiculously bad design that when someone chooses to play to a specific speaker that it doesn’t take priority over what was last conected! Does it expect me to go through multiple people and ask them if they’re connected to my speaker???? Please anyone if you can help because I’m ready to bin the whole system in favour of another brand.  Thanks