Transfer Sponsorship

hello everyone... i'm working as a cook here in al khobar, i've been here for about a year now and for the past months my company gave me like an installment salary... eventually, i supposed to get it every month for that is written in our contract but i'm receiving it like every 3 months. is it possible for me to transfer to another sponsor if they keep violating our agreement...i have read an article saying that my employer should not kept my passport... is it true that they can not take my personal document in which that the Gov't of the Philippines provided me, thank you,