Can you clarify your problem statement? What is not working?
If you're not a PSP, you're still able to decrypt the paymentData{} yourself which allows you to route the transaction to any PSP you choose.
Merchants can enable Apple Pay a couple of ways, either directly between merchant server and Apple, or through a PSP who can either host the entire payment flow or give you integration instructions and SDK.
If you can clarify we can get you on the right track,
Cheers.
Topic:
App & System Services
SubTopic:
Apple Pay