Roblox fraudulent charges

my daughter is 8 yo and is set up to only make purchases if I approve them. I now have over $900 Roblox charges that I did NOT approve that have been charged to my card since 3/2. How is this possible. I believe these are fraudulent charges that someone has either hacked her account or we are being taken advantage of. She cannot make a purchase alone. I must authorize the purchase 1st before it goes through. This makes zero since!