Do I need to file a response to an uncontested divorce?

My husband apparently filed for an uncontested divorce but I never received any notice of it. I did get a ‘default judgment’ in the mail, apparently because I didn’t respond to his divorce complaint. I’m not really contesting anything except we do have one joint credit card debt that he ran up. I want my name off of that account. Will the divorce automatically make that account his responsibility, or do I need to file some type of response to his divorce complaint? How can a default be entered by the court against me if my ex never gave me any notice when he filed?