Childs Apple ID

Hi all, I created my child an id through family sharing and all is working fine except from purchases.

When she tries to buy something through a game or download an app it tells her that she needs to verify the paypal account. We follow the instructions and it tells us that it has sent a code, which it hasnt to a number that doesnt exist and isnt linked to my Paypal so it just hangs there and doesnt let us continue to the purchase, totally stuck, Ive done all the resets - unlinked and linked paypal - added apple pay to the account.

When I added her apple ID I used a debit card but it still decides to bypass this to Paypal and wont let me delete it as a payment option! HELP it is driving me insane!