Immediately contact your insurance company. Make absolutely certain that you keep notes and proof if possible of how you notified them. If you haven’t made a claim to your insurance company in recent months or years then you probably need to talk to a lawyer about the matter as the incident you are being sued for might not be covered by insurance. Most courts require a response within 30 days from the date the complaint is served on you (some only 20 days). If you don’t respond within the time allowed by law then you basically have lost the case.