I have been careful to use only royalty free music in the mod.
The song "twinklebox" I obtained from here - http://freemusicarchive.org/music/Emphemetry/Twinklebox__Old_Dreams/
and I included it in the mod because it has this license
basically it allows me to share/use this song for non commercial purposes.
So I cannot understand why this song is being flagged up as claimed by believe music. It is possible that "Believe music" have signed Emphemetry (the creators of the song) since the song was created. However this page clearly states the license of the song and that it can be used for non commercial purposes.
You could dispute it, as the licence is clearly posted on the above site, however I leave this entirely up to you. Please let me know the outcome if you do dispute it, and I will remove the song if there is legitimate copyright claims on it (however there shouldnt be any).