Complex sentence: The relationship with Mercury Records soured quickly; the band felt betrayed and misunderstood by their label and as a result severed their ties with the label amidst the merger of Mercury Records, Island Records, Def Jam Records, and Polygram into the Universal Music Group.
Split into simpler sentences: The relationship with Mercury Records soured quickly as the band felt betrayed and misunderstood by the label. They severed their ties with the label amidst the merger of Mercury Records, Island Records, Def Jam Records, and Polygram into the Universal Music Group.