Amazon Order Delay and Poor Customer Service Problem

I ordered a dress from the Coesta Agahta seller on Amazon on July 29. The system indicated that the delivery would be made on July 31, but it has now been 7 days with no delivery. I contacted customer service, and they created a complaint for me. After waiting 48 hours, the seller still did not respond.
Additionally, I noticed that the same dress is available on Trendyol for ₺200 more. When I sought help, Amazon representative Ms. N*** abruptly hung up the phone when she couldn't resolve the issue. I cannot understand how a global company operates like this. It is very unprofessional to hang up on a customer.
I will no longer use Amazon for my purchases.