To cancel your ChatGPT subscription, use the same platform where you signed...

https://wiki-book.win/index.php/Why_Does_the_ChatGPT_App_Still_Say_Auto-Renews_After_I_Canceled_on_iPhone%3F

To cancel your ChatGPT subscription, use the same platform where you signed up—whether that’s the web, Apple App Store, Google Play, Stripe, Business portal, or API billing