why am i being charged 9.99 a month?

Hello, since 2 months I’ve been charged 9.99€ each month for unknown reasons. It does not appear in subscriptions, purchase history, nothing, except on my paypal which is my only method of payment. I know it is not apple music because i get charged the student 4.99, nor the 2TB iCloud storage because i pay 2.99 for that. it’s not a family member either for they do not use the same account as me.

I have noticed many other people asking the same question with no answer so please help.