Having control boxes behind the kick panel or under the seats or in the trunk behind the left and right wheel well trim is normal for all high end vehicles. BMW, Mecs, Bentley all have such control boxes in these locations. Oshan is no different
The question that comes to mind is how did the water get to this control box. Either some fool guy decided to wash the carpet with a water hose or this car has been an unfortunate victim of flood water. Either way this is not a warranty claim as @hash4u said Oshan is not to be blamed.
Your best bet, If you want keep the car, look for this part online. You might find it cheaper overseas however somtimes such parts have to be coded to the vehicle. .