Do I have a case against the police?

I recently had 6 officers come into my home without a warrant due to a domestic call that was made by my next door neighbor. They let themselves into my home after my roommate opened the door then came upstairs to the room. They seen my boyfriend rolling a blunt. They never identified themselves as police or explained why they were here. Once they seen the marijuana being rolled they then took it and searched my roommate and asked him if he had anything else. He then explained to them that he had more on him and in his room and gave it to them without question. They never arrested him or explained to him that he will ever get any summons for court. We just recently got court papers for possession and I''m not of why. The police said they will not charge anyone if they just received all of the marijuana. But he has been charged! Please can anyone help us??