What's Nissan doing about quality of their vehicl

We have a Nissan Qashqai, which we love! BUT, and this a big BUT, the tailgate on the boot has come off, and Nissan is quoting us 1000's of Rand, to fix this. I did a few checks on the Web, and this is a common problem, so I want to know why customers must pay for design flaws in what I consider to be an expensive vehicle? Surely the Supplier cannot expect customers to pay so much money for a flaw in their product? There are vehicles out there that are 30 years old, and their tailgate don't come off, why should we pay 1000's for a tailgate on a vehicle that isn't even 10 years old. I dont believe this should be considered as part of \wear and tear\".<br> <br> I look forward to hearing from the Supplier. "