seat belt came all the way out and the locking part broke

I was on my my way home last night and was rear ended on the freeway the guy who hit me was going about 65+ my car completely shut off on me. When he hit me I did have my seat belt on but it didnt seem to help. I flew into my stearing wheel and flew back and hit my head on the seat. The seat belt did not lock like it was suppose to it came all the way out then the locking mechanism broke inside. My car also said the air bags did deploy but they did not. From the in pack of how hard he hit me it should have gone off. I talked to a couple car saleman at dodge and they stated they should have came out and the seat belt should have proctected me more? My next step is contacting a lawyer on this matter, what if I get in another accident and they don't deploy again?