Re: App Store Refunds
For free trials of Apple's own products, if not cancelled at least 24 hours before expiry, and a refund is requested, then Apple may kindly, (or may not) approve a particular refund. ie: There's a legal agreement in place, that was accepted when requesting a free trial.
Eg: Legal - Apple Media Services - Apple
However: seems, in some cases Apple acts much like a bank does in transferring payment to a vendor or app developer. Then Apple doesn't have that money to refund. The app developer (or the app-vendor) does. Any refunds would have to come from the person holding your money.
Here's a link to Apple Support's article that explains in detail:
About purchases not billed through the App Store or Apple In-App Purchase - Apple Support
Eg: says:
"If you paid for an app, a purchase within an app, or a subscription outside of Apple’s ecosystem, contact the developer for billing support or a refund. Apple is unable to provide support for these purchases."
There's a lot more info., along with details, in that above linked article
or
There's other support articles online:
Eg: The best source of help for a product not made by Apple (a third-party product) is the company or person who made it—its vendor or developer: How to: Contact a third-party vendor - Apple Support
or
How to contact an app developer - Apple Support
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Apple also provides a Subscriptions and Billing Support website:
(Info. / support / contact options etc.)
Subscriptions and Billing - Official Apple Support