Someone’s using my daughter’s Apple ID to purchase Roblox and Robux. Her account is connected to mine. How do it stop this? Roblox says it apple’s problem

If the only indication of the charges is from an email or text, be aware that it may be a phishing attempt to get you to log in to a site that appears to be Apple and divulge your password or credit card information. See: Recognize and avoid phishing messages, phony support calls, and other scams - Apple Support

and Identify legitimate emails from the App Store or iTunes Store - Apple Support

If it is a real purchase, see the items in If you see "apple.com/bill" or an unfamiliar charge on your statement - Apple Support

including this in item 3:

Anyone who has your Apple ID password can make charges to your account. If you have unauthorized charges, Change your Apple ID password - Apple Support

Your daughter has either given her user name and password to someone else or she's buying them and doesn't want to get into trouble. Here's how to contact support:

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