Disappointed

A few weeks ago I noticed that the passage side was damp but I thought maybe I left the windows open Monday the 3rd of March after the heavy rains on the weekend I opened my car it was full of water inside . Went to Hyundai Umhlanga the assessed and told me that it was windscreen that had a gap because it was fitted with aftermarket windscreen, I asked what that meant they said it was not the original windscreen. I searched on Google and it meant just that and that parts don't usually fit .I have been in an accident from the time I brought the vehicle and now I'm told to claim from my insurance to a part that I didn't know was a replica . I bought that car like that and I'm being told of wear and tear of a windscreen that has never been replaced by me . I'm not accepting this why was I not told when I bought that vehicle that the windscreen is not the original. Now I must pay for it