The insurance companies for the at-fault driver are not in the business of paying claims unless they believe their insured is legally responsible for the accident and that your claimed injuries are related to the accident. They will conduct a full investigation of how the accident happened, which will include talking to their insured and trying to talk to you. If they talk to you about the accident, they will usually try to get you to say something that will prove harmful to your case. That is why I typically recommend that people avoid giving recorded statements to the insurance company.
The insurance company will also try to find evidence (either through talking to you or reviewing your medical records) that proves that your claimed injuries were not caused by the accident. Once again, their goal is to avoid paying any more than they believe they must.
If the insurance company determines that their insured is not legally responsible for the accident, they will deny your claim. At that point, your only recourse is to file a lawsuit against the at-fault driver. Before you do so, I highly recommend you talk to an experienced personal injury attorney.