Insurance is denying claim what action can I take

My car i20 sportz model has been and front bumper got damaged and is in service centre for damages, i approach to the insurance company and claim for the damages but they give me silly reasons that your car has already scratches on it and fog lamp of the bumper is already screwed and left side bumper has screw on it, i told him fog lamp has been screwed because it was coming out and right side of the bumper is also screwed bcoz it was coming out from the corner but they telling me that multiple damages not covered in claim, i told him it was major damage but they refuse