Complex sentence: EMI declined to release Paulina's first English crossover album, which was supposed to be the English version of "Planeta Paulina" album, because of that, Rubio got in a legal battle against EMI for not fulfilling the plans they had already planned.
Split into simpler sentences: EMI declined to release Paulina's first English crossover album, which was supposed to be the English version of the "Planeta Paulina" album. Because of that, Rubio got in a legal battle against EMI for not fulfilling what they had already planned.