What can I do if my landlord is unlawfully evicting me?

You have to wait until he gives you a three day notice and then sets the matter for an unlawful detainer action. At that point you can raise the defense that you paid and at trial bring in what evidence [cancelled checks, etc.] you have. You can also raise any breaches of the law; not knowing what violations you claim occurred, I can not say if you can raise them before trial or if they are relevant to the issues at trial.

You must immediately file a response to the eviction papers. They should show you where to file a response, in other words which court. Then the Judge will schedule a hearing so you can tell your story.