Copyright claimed by someone else for your music.

I recently posted a video to youtube using a track from rush, neo soul sunrise by splice originals. The video was copy right claimed for the music but when I looked into it I found it was claimed by a company sellbuymusic and they said the song title was unemployed works. It appears they used your song and added their own tracks, beat, and synth to it and posted it as their own. After looking at their channel it seems like that's what their are doing with a lot of songs.