Refund

Hi good evening my son ipad was broken last month and i take new one by apple care at this time they did backup to all data the proplem that i make save to credit card ehen i make back up i got it back while i remove before.my son by misrake did many payment from game rolblox about 3000dirham.very big amount and i did not need it and he did not know he is 5years.if you can help me to got this amount back i will be very thankful for you.i know it is strange to request that but really it is by mistake if you can help