How can I dispute unauthorized iCloud charges?

How do you know it was for iCloud exactly?

Apple charges do not specify what they are for on your payment method's statement. They'll just appear as "apple.com/bill" and could be for anything sold or offered by Apple, including other subscriptions like News+ or TV+ etc... as well as any purchases in the iTunes, iBooks or App Stores.

If you have a charge from "apple.com./bill" see the following support document to identify it, and request a refund if required.

click here ➜ Get help with charges from apple.com/bill - Apple Support

If this charge is appearing anywhere else, like in an email or text message, then it's likely a scam.

click here ➜ Identify legitimate emails from the App Store or iTunes Store - Apple Support

and here ➜ Recognize and avoid social engineering schemes including phishing messages, phony support calls, and other scams - Apple Support