Issue with family payment

Hello, I am the family link administrator for my daughter. I purchased an e-card so she could buy packs in her game. It's impossible to use it on her phone, telling her that the administrator has to enter the code. I ended up downloading this code and thus credited my Google Play account with 15 euros. At this point, I can't use this money on my daughter's phone. I specify that I have removed all restrictions for permissions and purchases. What should I do?
I tried to delete her family link account but was told it's impossible because she is under 15 years old!!! I then tried to change her age but that was also impossible... Thank you for helping me if you have a solution????????????

Configuration: Android / Chrome 91.0.4472.88