The same things happen to me. Spotify changes songs by itself on both my iphone 6s and samsung galaxy s9 or start to play song that are not in my playlist. Once it started to broadcat music by itself on my tv in the middle of the night. Very scary. Could you help?
My account started having this same problem months ago while using Spotify on my I-Phone. Then the same issues started happening on my PC at home. Very frustraighting. I looked at all the replies online I could and there is no real answer to the problem. Spotifies support has no real replies to solve the issue. I updated drives and all the simple items I coud think of and read what others had tried. Nothing worked.
Then I found what solved my issues:
Go to account and scroll down to Apps. In Apps, Revoke access to ever App, even Spotify.
After I did this it solved all my issues on both my I-phone and PC. Hoppe this helps.