Traffic accident, hit my car, judged that the other party was fully responsible, but after repairing the car, I couldn't contact the other party, and the other party refused to pay the claim!

You can ask the traffic police to call him first. If he doesn't pick up or compensate you, you can go to the insurance company where your car is insured, give the accident certificate of the traffic police to your insurance company, and let your insurance company make subrogation compensation to compensate you for the cost of repairing the car. Don't worry about the latter, your insurance company will take care of it.