Rear Suspension Springs problems of the 2004 Nissan Xterra

Passenger side rear leaf spring broke while driving on the freeway, almost puncturing gas tank according to the mechanic. The driver's side rear leaf spring broke while driving on city streets. I was advised by my mechanic that this was definitely an item that should not have failed and it is most likely due to defective part, as the metal layered leaf spring should not break. The mechanic advised that since the vehicle is not one that is driven in a manner of off roading, that the failed leaf spring was defective and something that should be investigated by the authorities perhaps, as a recall item. He advised that I should file a complaint and I have reviewed this site to determine that many others have had issue with the leaf springs breaking. Please investigate. Thank you.