In principle, it's the right to do, but in practice it will never work: Police cover each other's backs, intimidate witnesses and actively subvert justice and decency whether they are the ones being investigated or when they interrogate witnesses. The whole refusing to take a complaint is very, very typical actually - That's another way the police use to intimidate. Standard policy is normally to receive a form, you fill it out, you return it with the information needed to file it, and that's it - The complaint is filed. Police will, however, go out of their way to attempt to confuse and deceive you. Take a look at this video for example:
[youtube]http://www.youtube.com/watch?v=p53ky3RIjfU[/youtube]
You go to file a complaint, and you'll get your head smashed into the plexiglass, charged by police for a made-up crime, and the justice system will side with the police.