Poor Customer Service After Checkout Error

Very disappointing customer service. I initially selected the King-size comforter while shopping on Macy's website. However, somewhere between selecting the item and completing checkout, the size unexpectedly changed to Twin without my noticing. When I received the order, I realized I had been sent a Twin comforter. I contacted Macy's customer service, and the representative simply told me that my order showed Twin, without acknowledging that the size may have changed during the checkout process. I wasn't asking for a refund—I only wanted to exchange it for the correct King size. Unfortunately, the representative was unwilling to help or offer any reasonable solution. I expected much better customer service from Macy's. This experience was frustrating and disappointing, and I hope Macy's improves how it handles situations like this.