You may want to hire a licensed engineer to perform an investigation inspection on the structure, and provide a written report on his/her findings. The drawings used by the contractor would need to be provided. The engineer would identify the fasteners, anchors, clips, etc., used, and specify if the materials were used as listed by the manufacturer(s), whether or not they were specified on the drawings. Without the benefit of a permit, the best course of action may be to provide as many factual pieces of evidence that indicates the incorrect use of materials by the contractor.