Rear Suspension Axle problems of the 2007 Nissan Sentra

Rear tires are wornout @ 11,000 miles. Nissan replaced 2 rear axles and rear suspension assembly and 2 rear tires. They changed the alignment specs and said it was fine. Consumer affairs didn't answer calls for 2 months. Inspector checked the rear tires that had just been rotated from the front and said they didn't show signs out being out of alignment. They wouldn't contact their factory in TN / safety engineer who had requested the original rear tires be shipped to them. A similar vehicle was checked by the dealership and it too had alignment specs that were out and similar to our vehicle. We have 24000 miles and ready for a second set of tires. Still out of alignment, has always been out of alignment, technicians state it'll never be in alignment because there's an engineering problem.