Bad service

I took my car in to Nissan Hatfield as the driver's door to my bakkie is letting it water when it's raining or the car is getting washed. Louis was my technician for the day. I received a call later in the day to inform me that they will not be assisting me as my passenger door shows that it's been tempered with.i have sent emails to Nissan with no feedback asking for assistance. I don't understand how the passenger door affects the driver's door. I also do not see any signs of the passenger door being tampered with. I need answers and it seems like Nissan is not interested in resolving my query. The service is appalling and the water damaging my car and who will be responsible for these further damages caused by their lack of urgency in assisting me and not even bothering to claim from the warranty covers they sold me with the vehicle?