Unable to update child age on my Family Sharing Apple Account
I want to update my child age (previously I created adult account in Family).
would like to change the date of birth for the Apple Account. This will convert account to an adult account. Learn More.To approve this change, please click ‘Approve request’ and sign in with your Apple Account
But after click on Approve Request I see
A valid card or mobile phone billing method confirms you can provide parental consent.
But I already have two mobile phones as billing method..
Could this be because my account is from Russia?
[Re-Titled by Moderator]
Original Title: Can not update childs age