Zara Dress Order Issue and Missing Button Problem

I ordered a dress from Zara's website, but it arrived with a missing button. I reported this issue to seek a resolution, but they stated that the problem was not on their end. I cannot understand how such a large company can send a defective product and refuse to acknowledge it.
It is not my fault that they did not check the items before packaging. I plan to escalate this complaint to consumer rights organizations. I expect better quality control and customer service from a reputable brand like Zara.