I would contact the police with what info you have. If you have the plate they should be able to locate the owner and either pull his insurance info or track them down to get it again. Also you could check with the insurance company if just the policy number is wrong the company you are filing a claim with should be able to look them up by name and address. If you are unable to find him in any way try your own insurance company. If you have uninsured coverage they could possibly help remedy the situation. Hope this helps and you can find the information you need.