Warranty insurance Used cars vs. warranty

Hello forum, I hope I am in the right subforum with my question here: I have purchased a used car with Mapfrey guarantee insurance. The first damage occurred even after 2 weeks in the amount of 700 Euro. The guarantee assumes the costs after some round-and-round proportionally, but material costs only to 50 percent, about 150 Euro remain open. The dealer thinks that I remain on this 150 Euro. The question: Since I have at the same time claim to warranty, the Is there a basis that someone could give me? PS: I know that there is no legal advice here, but I am interested in the principle of who is in the right here. I am not interested in the right here.