Unauthorized purchase
I just need a phone number to talk to someone about an email I received about a purchase I didn’t make
The email may not even be from Apple, it may be from someone impersonating Apple trying to steal information, hoping you'll type in your credentials on a fake form or website.
If it did come from Apple, there are online resources to check details about the purchases and report unauthorized activity. See "I got an email saying I bought something from the iTunes Store, but I didn't!"