Apple processes all charges for the App Store. For your security and privacy, only Apple knows your purchase, payment, and credit card information.
Any request for a refund has to be done through Apple. Similar to the way that if you bought a non-Apple product in a physical Apple Store you would have to go back to the Apple Store to request a refund.
The purchase of a subscription is a contract between you and Apple and is governed by these Terms and Conditions: https://www.apple.com/legal/internet-services/itunes/
Apple may refuse a refund request if they find evidence of fraud, abuse, or unlawful or manipulative behavior. The decision to offer a refund is entirely up to Apple.