What does islam say about oppression?

My country is going through a rough time due to corruption at every level. I'll give a few examples: 99% of govt jobs are given to people of a certain party. Unless your father was a big dog in that party you have no chance of govt jobs. Exam questions leaks for every exams. You came first on a national exam? Gues what you don't matter the party member gets priorities anyway. You can'tcomplain or you'll be arrested for lying, you can't protest or you'll be badly beaten by the government's hired mfkers. And they'll even hit college girls. And police will not do shit. every day you find news of corruption with proof and you can't do shit about it. And the worst of all the prime minister jokes and admits to the corruption of the party and vip guards on national television but no one can do shit. So yeah looking for what Islam has said for us to do about it?