You must have done something to initiate the subscription if that is indeed what it is. They don't start as if by magic.
Also, any charges made by Apple would not identify directly what they are for specifically on your payment method's statement. They would just appear as "apple.com/bill", so how do you know its specifically for Apple Music?
If it is for Apple Music, you can go into your subscription list and cancel it directly there. Once cancelled, you can contact Apple Support for a refund.
click here ➜ If you want to cancel a subscription from Apple - Apple Support
and here ➜ Contact Apple Support to request a refund for a cancelled subscription