PREMIUM GLITCH


If you bought through one of the apps, it can take some time to be applied. Also, it uses the email address associated with the app store account, so if that does not match the email on the chess.com account, it won't be applied and you'll likely need to contact support directly.
https://support.chess.com/article/346-contact-us


That's not a normal option for memberships, so if that was something offered to your guardian, it probably needs manual intervention.