Why i am charged

To unsuscribe from an in-app purchase please see View, change, or cancel your subscriptions - Apple Support

This is a user to user forum: you are not talking to Apple here and we don't have access to your account, so if you can't work out what is going on you need to contact Support using the link in the first page I linked to above.

Please see If you see apple.com/bill, itunes.com/bill, or an unfamiliar charge on your statement - Apple Support

Romina,

In such a situation, I would contact directly iTunes Store Support team and explain your problem, filling out and sending them this form:--> iTunes Store – Contact Us – Apple Support

Regards

Giulio