I have an unknown charge for $4.99

What was the result when you followed the guidance in the Related Article above your name on this page, that you were reading just before you posted here? If the Related Article doesn't answer your question please post back with more details about the issue and another user in this user-to-user forum will try to help.

Do you see it if you log in to https://reportaproblem.apple.com? If not, it was a different Apple ID that is using your payment method. Another family member, perhaps?