Payment problems come from the payment method on your Apple ID or Google account, so that's where to fix them.
On iOS
Go to Settings > [your name] > Payment & Shipping and double check your payment settings.
For more, see Apple’s guide to changing your payment method.
On Android
On your computer, go to your Google Play account.
Select Edit payment methods. You will go to your pay.google.com account.
On the left, select Payment methods.
For more, see Google Play’s guide to payment methods.