From Account Settings in iOS:
From Subscription Settings in iOS:
Open your Chatbooks app and tap on the “setting” in the top-right corner of your screen
Tap on "Payment"
Click on “payment” and enter your new payment details
Tap “Update Card” Or "Add Card" to apply these changes to your Monthbooks or Monthly Minis subscription
In Account Settings From Android:
In Subscription Settings From Android
Open your Chatbooks app and tap on the subscription or Series you’d like to update the payment method for
In the blue “subscription settings” section, click on “edit,” then tap “payment”
Enter your new payment method by tapping on the blue “+” sign in the bottom right corner
Check out how to update your credit card on your account HERE!