"Phantom" device, how to remove?

[Stooovie]

Hi, I have a "phantom" device (two actually) of devicefamily "WHA" and deviceType A3C9PE6TNYLTCH. These should be Multiroom groups but they are NOT in my Alexa account. I have been on support chat with five different Amazon techs in a row but to no avail. No common troubleshooting like uninstall/reinstall/deregeister/reregister, deleting all multiroom groups, nothing helps.
These "phantom" devices pop up in Spotify as well as in Alexa app. Cannot be deleted as they don't really exist. They also SOMETIMES duplicate (yesterday I had SEVEN duplicates of this "Living Room" bogus device!!). The icon shows two speakers, so it should be a multiroom group.

Any clues? How can I destroy these? Weird thing is, when I actually play audio to these, it's one of my Echos (Echo Show 5 2nd gen) that plays the audio. When I "forget" the device, it disappears until audio is played to any of my Echo Dots (Show and two 3rd gen Dots). Thanks!