Legal Question in Civil Litigation in California

You need to consult with a competent attorney as soon as possible. That attorney is going to want copies of the summons, complaint, and the other side's proof of service on you. The attorney will want to speak to you as to when you first learned of this, and get details from you. Don't wait around on this.

Yes, you must handle this immediately, because the Code of Civil Procedure �473 provides time limits for doing so. Your motion to set aside must also attach a proposed answer to the complaint.

Concerned? No, not unless you care about a judgment against you.

You must act immediately. If you don't know how to represent yourself effectively against an experienced attorney intending to get such judgment, then hire an attorney who does know, who will try to set aside the default and defend the case for you. If serious about hiring counsel to help in this, and if the charges are in SoCal courts, feel free to contact me.