How do I remove a blocked card

See -> Remove a payment method from your Apple ID

Remove a payment method from your Apple ID - Apple Support

⤵️

If you can't remove a payment method

If you have subscriptions like iCloud+, have an unpaid balance, or you use purchase sharing, you must keep at least one payment method on file.

• Do you have a subscription? You can cancel iCloud+ and cancel other subscriptions from Apple. When your subscription period is over, remove your payment method.
• If you're in a Family Sharing group and you use purchase sharing, the family organizer must have a payment method on file. If you're the family organizer, turn off purchase sharing, then remove the payment method.
• If you have an unpaid balance, you might not be able to remove a payment method. Instead, change your payment method.
• 👉 If you still can't remove a payment method, contact Apple Support.

See this article about updating payment methods on various platforms (iPhone, Mac, etc.): If you need to change or update your Apple ID payment method - Apple Support

"If you change your address, the credit or debit card information that you use with your Apple ID might be automatically updated by your financial institution, and you don't need to take action. But if there's an issue [such as you having a subscription or being a Family Sharing Organizer], add a new card first, then remove the old card."

Here is how you update your payment method on an iPhone or iPad:

1. Open the Settings app.

2. Tap your name.

3. Tap Payment & Shipping. You might be asked to sign in with your Apple ID.

4. Tap Add Payment Method, enter the new payment method, then tap Done.

5. Tap Edit.

6. Tap the red delete button next to the old payment method, then tap Delete.

Update your payment method on a Mac

1. Open the App Store.

2. Click your name or the Sign In button.

3. Click Account Settings.

4. Next to Payment Information, click Manage Payments. (If you're using an older version of macOS, click Edit next to Payment Type.)

5. Click Add Payment, then enter the new payment method. Click Done.

According to Add a payment method to your Apple ID - Apple Support you can also add a payment method after signing in to https://appleid.apple.com .

In some countries and regions, when you edit payment information online at appleid.apple.com , additional payment methods might be removed from your account automatically.

Add a valid new card before you can remove an old card.

If one or more of the following 6 options are true then you can't choose None as a payment method then the Billing information is needed . The "None" option will not appear...

1. If you have an unpaid balance or payment due
2. If you have a subscription that automatically renews
3. If you're using the iTunes Store or App Store for the first time
4. If you are not in the country or region you’re creating an Apple ID for
5. If you changed your country or region
6. If you're a part of Family Sharing