How can I stop unauthorized charges from iTunes.com?

This is primarily a user-to-user support forum; other Apple users like you. We don't have access to information about charges to your account. Apple has a support article about charges — see each of the steps in the following instructions. They include information on contacting Apple Support if the other steps don't help. See: If you see 'apple.com/bill' on your billing statement - Apple Support

If the billing is for a subscription, there is an Apple article that explains how to cancel subscriptions. Click on the following link: If you want to cancel a subscription from Apple - Apple Support