Complex sentence: Kauer balked at working with Grofe again over concerns about timely payment for his services, and upon a recommendation by Tony di Marco, Grofe instead contracted with rock musician Sean Bonniwell to create the music score.
Split into simpler sentences: Kauer balked at working with Grofe again over concerns about fees. Upon a recommendation by Tony di Marco, Grofe instead contracted with rock musician Sean Bonniwell to create the music score.