V50 Preheating / Used car warranty

Hello together, have me here registered in the hope that someone can help me here further. I bought me before 4 months ago. A V50 2.0D. The car is BJ. 2004 and has now 133000km on it ( when buying he had 122000km) unfortunately had to find out that the heater does not work. Is probably the control unit or the fan. When the vehicle was handed over the heating was also not at, because it was about 20degrees warm thought it is simply too warm that it does not concern. Since I bought the car from a VW dealer ( about 200km away from me) and have the PerfectCar guarantee, I thought that the thing is probably a case for the guarantee. It is not only a stand heating but a heater which was unlocked as a stand heating. According to the dealer however, there is not taken over because he has sold me the vehicle explicitly with stand heating. Also the “nice” lady from the VW insurance says there is not only a stand heating but a heater which was unlocked as a stand heating. But because not so much because he has taken over to me because of the warranty can help me from the nice thanks already.