I feel very sorry for the OP. Unfortunately, this is what happens when you're not a customer of the organization that protects you. Police officers will not be paid less if they mistreat the people they're supposed to protect. To get them to justice, as was mentioned in another comment, would cost tons of money and time and there's no guarantee of any kind of result. They know it.
The only places where police is actually humane and does mostly good are Scandinavian countries. My explanation of that phenomenon is that those countries are small (both in territory and number of citizens) and are, indeed, operate like small companies. Thus it's relatively easy to keep them accountable. Of course, many other small countries have very corrupt police, so this can only account for a part of the explanation.
My opinion is that where there is no market mechanism to effectively communicate customer satisfaction, you will see abuse. People see it again and again, yet they keep paying taxes to sponsor this shit, because they are being told there will be anarchy or the poor wouldn't have the money to hire a private police protection. I wonder if the poor would actually be better off without police "protection" at all. After all, they are mostly after people who conduct victimless crimes and are never there when a woman is getting raped or someone's being mugged. That's not protection, that's extortion.