I was hit by a girl driving her friends truck. She wasn't on policy. Who's responsible?

I was hit by a girl driving her friends truck. She wasn't on policy. Truck owner was insured at time of accident but isn't now. His insurance denied my claim because even though he was insured at the time if the accident, they couldn't contact him after only mailing and calling, so they denied claim because they couldn't get further information from him about the girl driving. So is the insurance company still liable since the truck owner was insured at the time if accident? Can they deny my claim just because they cant contact the insured? Who's responsible: insurance, insured, it friend driving vehicle. Do I take it to small claims and if so against whom? Unlikely I will collect on insured or the friend because they are shall we say less than polite society with criminal history. I feel the insurance is responsible but I don't want to file on mine then try to subrogate. She was not ticketed but cop stated she was at fault which is here say in court. The report state she hit me though