I am a CA lawyer.  If the other driver had a stop sign and you did not, he would be at fault.  If you were going too fast, as they allege, there may be an issue of comparative negligence.  That would depend on circumstances.  As a practical matter, the fact that he is not providing you with his insurance leads me to believe he may not have insurance.  (This is speculation on my part).  You need to complete an SR-1 form and file it with the DMV.  Also, you need to report this matter to your own insurance company.  If you are covered with collision coverage, you can get your car fixed and pay the deductible. 

I also suggest that you take photographs of the intersection along with photographs of the damage to your car.  If you have any injuries, you should consult a lawyer.  This website has a list of lawyers so start your search here.