How do I resolve an unpaid third-party subscription through Apple Pay?

To me it sounds like something the streaming service needs to resolve with Apple. If you want to get involved in this:

This support article has various country telephone numbers for contacting Apple for support and service ➔ Contact Apple Support - Apple Support For some countries look under “Other” listing at the end of the list. Not every country has telephone support, and phone numbers may only work when calling from the same country.

For chat help with a USA Apple Account —>

https://getsupport.apple.com/?caller=kbase&PGF=PGF63005&category_id=SC0998&symptom_id=20198

Using Apple Pay does not mean that Apple is paying the third party provider, the streaming service is billing your bank directly with the unique code that your bank sent to your device when you added that card. No money is being transferred through Apple.

Is this a charge billed through your Apple Account using an in-app purchase, and not actually Apple Pay?

MrSpkr42 wrote:

Yes … Apple Account, not Apple Pay. Apologies for the incorrect nomeclature.

Ok, it may help to know the streaming service. Each service also has an account that you use on their service and that account needs to be linked to the Apple Account used to pay for the subscription. It is not enough to just use the same email address for the streaming service to have the account automatically linked to your Apple Account.