The support article If you see 'apple.com/bill' on your billing statement - Apple Support and the related article Get help with charges from apple.com/bill - Apple Support explain how you can check your iTunes and App Stores purchase history, cancel subscriptions (remember that these need to be canceled at least 24 hours in advance), and track possible sources of unrecognized Apple charges you may see on a bill. These may be purchases by Family Sharing members, others sharing your card (such as a spouse or partner, or a second Apple Account you have; you may not see a receipt).
The article also provides a specific link for contacting Apple if you cannot trace the source of charges, e.g., if you subscribed to something directly with a third party, see: About purchases not billed through the App Store or Apple In-App Purchase - Apple Support instead. In that case you need to work directly with the vendor, not Apple. See also: Fabulous SAS - Unethical app, please dele… - Apple Community
If using Family Sharing and viewing purchase history under Report A Problem, make sure the “Apple Account” box is set to “All.” If a purchase is listed in your purchase history and you want to ask for a refund, read this article about how to request a refund for apps or content that you bought from Apple ➞ Request a refund for apps or content that you bought from Apple - Apple Support Remember that many apps have trial periods with subscriptions that then start automatically unless you cancel them in time. If a Family Sharing member made the purchase then you need to discuss this with that person. They would have to initiate any refund request.
If neither you, nor Apple, nor a Family Sharing member can account for a charge and it ONLY appears on a bill for a charge card you alone control, you may have been the victim of card fraud. Contact your financial institution immediately. Any reimbursement would have to come from them, not Apple. More here —> Refund Rejected on fraudulent transaction - Apple Community
If you want to contact Apple to dispute a refund refusal, try a telephone or chat method, click here --> Choose your country or region - Official Apple Support Select your country, then a product. If you don't see one that handles your issue then keep experimenting with selections until you reach one that gets you a chat session or a telephone call and get the representative to redirect you.
or:
"See a list of Apple phone numbers around the world." Click here --> Contact Apple Support - Apple Support
Once you have been denied twice, or it says the decision is final, then in my opinion it is probably pointless contacting Apple any more. At this stage all you can do is try to discover who made these subscriptions and resolve this with them. My guess it is a Family Sharing member.