If you did not go to the hospital after a wreck but a couple weeks later your back is hurting pretty bad.. what to do? Wreck caused by brake job

Brake job performed by the dealer of the car. They went out and I took my car into a guard rail so I wouldn't hit 2 vehicles full of people. Full coverage insurance, no rental, and $4800 in body damage but I come out of pocket on the brakes. N--O. I'm not doing that whatsoever. I am lucky that I'm not dead. Something needs to happen. I've got 24 hours to give insurance a response. In the meantime, ive had no vehicle for 3 weeks, and they want me to pay for a new brakes that was their fault in the first place. Please help me