For insurers to keep their claim costs down, many of them will require their authorised repairers to use non-genuine, pattern parts for repairs. So as barrym381 has said, most body shops will use non-OEM parts.
Many years ago I rejected a repair to previous car I owned. I didn't have a problem with the new replacement panels used, but the new paint was a really poor colour match compared to the original paint. I got the insurance company to inspect it and they agreed with me. The outcome was my insurer agreeing for the repairer to repaint the repaired area again. So if you're not satisfied with the repairs, be persistent until it has been rectified to your satisfaction.
Oh, and welcome to the forum.