Son made illegal purchase

Hello DMn7k​,

in general, purchases of in-game currency are non-refundable, as described here. However, if you've cancelled the order and got your money back, I'd wait a while longer to see if the in-game currency disappears and otherwise maybe contact EA Support.

It's important that you make sure your son doesn't have access to your game account and payment options, so that such situations cannot arise. EA cannot distinguish between purchases made by you vs your son, if those are being made through the same means and account, and can therefore not make any exceptions regarding refunds, if one is still needed after all.