Amazon Sent the Wrong Product and Hasn’t Fixed the Issue Despite My Complaint

I bought things on Amazon, but when they delivered, it was a totally different package than what I ordered. Right away, I called Amazon's customer service in the hopes of getting a quick answer. But, even though they wrote back, nothing has been done to fix the problem. I even have the bill for the wrong item that was sent, but Amazon doesn't want to do anything to fix the problem. I thought a company this size would have much better customer service. It's annoying that I paid for things I never got, and I feel let down by their lack of help. That being said, I hope Amazon steps in and fixes this right away.