What is apple email address for requesting refund

I was charged 6.83 on my bank account and it says that it’s from apple. I went through my purchase history on the App Store and it only says that I was charged for Apple Music only. I’m not sure what the the $6.83 charge was for. I was wondering if you’re able to tell me what that charge was for so I can confirm if it’s correct or not. Thank you!