I have a 2015 golf sportwagon and the pump in the ad blue tank is not working so the car cannot be used until the ad blue tank is replaced. This is covered under the warrantee. My car has been at the dealership since January 2023. Thankfully my dealership has been letting me drive a loaner. There is no date on when this part will be available. It is not being manufactured anymore. Originally they got dates in april, then may, then june, then july and now they have no date. What remedy do I have if the car can not be fixed?