I was charged 10.99€ for some bill iTunes thing

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. See each of the steps in the following instructions. They include information on contacting Apple Support if the other steps don't help: If you see 'apple.com/bill' or an unfamiliar charge on your statement - Apple Support

everything you should do to understand where is comes from is perfectly described here:

https://discussions.apple.com/thread/252471624