Faulty Hot Wheels Car Ruins My Son's Collection - Poor Quality Control

We bought a Hot Wheels car for my son’s collection, only to realize later that it was defective. We buy these toys to make our kids happy, but this time, my 4-year-old was really upset because he couldn’t play with the car properly—the bottom piece keeps falling off. He doesn’t understand and keeps saying, “My car is broken.” Why is a toy made for kids packaged without proper quality checks? Are we considered a third-rate country that you sell faulty toys to? Lately, every car we’ve bought has had some kind of issue, whether it's missing mirrors or other defects. This time, I'm particularly upset. Please make up for this mistake. Thank you in advance.