Complex sentence: The Malaysian hip hop scene started in 1990s with rap groups such as KRU, 4U2C and NICO, but their so-called "Rap music" wasn't accepted by the mainstream community and so they had to changed to a more pop-ish sound.
Split into simpler sentences: The Malaysian hip hop scene started in 1990s with groups such as 4U2C, NICO, KRU. Their so-called "Rap music" wasn't accepted by the mainstream community and they had to changed to a more pop-ish sound.