Apple can’t help, because they are not the card issuer. Only the card issuer can assist in resolving the issue. The issue is much more complex than what you may believe. There are three parties involved and adding the card to other devices was not a good idea. Many banks may take that as potentially fraudulent activity.
The approval for adding a card to Apple Pay involves 2 or 3 different entities, your bank, the Payment Network Operator (Visa, MasterCard, American Express etc.) and possibly the Token Service Provider. Apple plays very little role in the approval process.
This is the process. Apple cannot approve it decline a card for Apple Pay. Only the parties mentioned above. Apple’s role is limited to sharing information about you and your device. This is only an informational role, not an approval role. Your bank, PNO or TSP are blocking you, the card and the device.
>>Adding credit or debit cards manually
To add a card manually, the name, card number, expiry date and CVV are used to facilitate the provisioning process. From within Settings, Apple Wallet or the Apple Watch app, users can enter that information either by typing or by using the device’s camera. When the camera captures the card information, Apple attempts to populate the name, card number and expiry date. The photo is never saved to the device or stored in the photo library. After all the fields are filled in, the Check Card process verifies the fields other than the CVV. They are then encrypted and sent to the Apple Pay server. If a terms and conditions ID is returned with the Check Card process, Apple downloads and displays the terms and conditions of the card issuer to the user. If the user accepts the terms and conditions, Apple sends the ID of the terms that were accepted as well as the CVV to the Link and Provision process. Additionally, as part of the Link and Provision process, Apple shares information from the device with the card issuer or network. This includes information about (a) the user’s iTunes and App Store account activity (for example, whether the user has a long history of transactions within iTunes), (b) the user’s device (for example, the phone number, name and model of the user’s device plus any companion Apple device necessary to set up Apple Pay), and (c) the user’s approximate location at the time the user adds their card (if the user has Location Services enabled). Using this information, the card issuer determines whether to approve adding the card to Apple Pay.
As the result of the Link and Provision process, two things occur:
1) The device begins to download the Apple Wallet pass file representing the credit or debit card.
2) The device begins to bind the card to the Secure Element. The pass file contains URLs to download card art, metadata about the card such as contact information, the related issuer’s app and supported features. It also contains the pass state, which includes information such as whether the personalizing of the Secure Element has completed, whether the card is currently suspended by the card issuer or whether additional verification is required before the card can make payments with Apple Pay.<<
Card provisioning security overview - Apple Support