Legal Question in Credit and Debt Law in California

You will want to get a copy of the lawsuit from the court, as well as the proof of service that was filed, if any. Perhaps you have not yet been served with the summons and complaint, and that's why you only knew about it from a third-party contact. Once you are personally served (or another adult in your residence is served and a copy is mailed to you), you should file a responsive pleading within 30 days -- an answer, demurrer, and/or motion to strike.

Sometimes, especially on old credit card debts, the debtor has moved and it takes a while for the bank to locate the debtor's most recent address to serve the summons and complaint on the debtor/defendant. The fact that you received a letter indicates that your address on the complaint attachment probably contains your present address.