Other Fuel System Tank Filling/charging problems of the 2010 BMW 528

While having my oil changed, I told the mechanic that I smelled a little bit of gasoline when driving and to check it out. I was shown that under the back seat, behind the driver side there is a sending unit and a fuel line that transfers gas from one tank to another. This plastic component has a tip where the fuel line connects. This tip cracked and broke (no idea why), leaking and pooling gasoline inside the car, directly underneath the passenger seat and filling the car with highly combustible fumes. So much so that the mechanic I took this car to, would not let me drive it out of there. I had to have it towed to a dealership. BMW customer relations had me leave this car for five days at a BMW dealership while they went through their process. Then, they informed me they assume no responsibility for this and they do not consider this a defect or a flawed design. My car is only five years old and is kept in perfect condition. Please look into this. I fear I will read about some person or family being burned alive and I feel I have to do something. I have the defective parts if you need them.