Legal Question in Civil Rights Law in California

Not enough information. If it is a regular (non small claims) civil case there won't be a "court date," if you don't answer within 30 days there will be a default judgment. Improper service can be challenged, default judgments can be set aside, and creditors who serve you at the wrong address can be sued for unfair debt collection practices.

If a small claims case, you risk a default if you don't appear, as the plaintiff likely filed a Proof of Service. You'd have to contest that Proof, and in doing so provide him your current address where you can be served again..

Fighting over service is generally a waste of time and money, making the plaintiff spend money to reserve you or file Opposition pleadings to your Motion. Then, if plaintiff wins his case later, those fees and costs get charged to you in a judgment.

Now, if this is Superior Court, you might as well deal with the lawsuit defense. If serious about hiring counsel to do so, feel free to contact me.