child cannot be added because they already have apple cash enabled

Hi, this is an easy solution with a few steps.

First you have to close the child's account

Close your account

Before you close your account, make sure that your balance is $0 and that you don't have pending transactions. To check your balance, go to your card info. You can transfer money to your bank, spend it, or send it to someone.

When your balance is $0, contact us to close your account:

1. Go to your card info:

• • iPhone: Open the Wallet app, tap your Apple Cash card, then tap . Tap the Info tab.
  • iPad: Open the Settings app, tap Wallet & Apple Pay, then tap your Apple Cash card. Tap the Info tab.
  • Apple Watch: Open the Apple Watch app on your iPhone, tap Wallet & Apple Pay, then tap your Apple Cash card.

1. Tap Contact Apple, then tap Call.

Then you go here - Set up and use Apple Cash Family

Since it was a child then their Apple ID should not have too much attached to it.

turning it off does not do anything you have to call Apple and have them close that account.