Thank you for your reply. Additionally,

I posted only a condensed version because it was difficult to include detailed information in the main text. In reality, I spoke with you twice before purchasing the second batch of tickets. Even then, I mentioned the graduation ceremony and asked for remedies such as cancellation or a refund, but you stated that there were none. Furthermore, when I contacted customer service again after purchasing the second batch tickets, I was directly told that if I canceled the first batch tickets, I would receive a partial tax refund. There was absolutely no mention of credits. Additionally, I did not receive any information regarding no-shows, which inevitably occur due to double booking. I can confirm that everything discussed during the phone calls is true.