ChatGPT Charges My Card for a Subscription That Never Appeared in My Account

I signed up for a 1-month free trial on the ChatGPT app. I got this trial on May 21st, and I expected it to show up in the subscriptions section, since I was planning to cancel it myself before it expired. However, despite checking repeatedly, I never saw any ChatGPT entry in my subscriptions, so I assumed this was simply how the system worked for a free trial.
Today, on June 21st, I noticed a charge of about $27 taken from my credit card. It was never possible for me to cancel a membership on my own that wasn't even showing up in my subscriptions in the first place. I neither approved such a high charge on my card, nor was I able to see the subscription transparently.
I don't accept ChatGPT charging me without clearly showing the subscription in my account's subscriptions list. I am requesting a refund of the approximately $27 wrongfully charged to my card, and I want my subscription terminated immediately.