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Login ID would be your email address you registered with your Kindle. Try that.
If you don't remember your password, then you can reset the password ***** this link--> https://www.amazon.com/gp/css/account/forgot-password/email.html
or from here --> https://www.amazon.com/gp/help/customer/display.html?nodeId=201121280
After resetting the password, follow the steps below to change the credit card details on your Amazon account.
Go to Manage Your Content and Devices page -----> https://www.amazon.com/mycd
Click on Setting tab, select Edit Payment Method below Digital Payment Settings.
Select the credit card information, or add a new card, and then click Continue.
Enter the billing address, and then click Continue. You will be taken back to the Kindle Payment Settings page where you can view your edited 1-Click payment method.
When you change the card details from there, the card details on the Kindle will also be changed automatically.
If the changes doesn't reflect on your Kindle, then reset the Kindle and see if it works or not. Press and hold down (or slide) the Power button for full 20 seconds and this will reset the Kindle.
If that didn't work, then you will have to de-register the Kindle and re-register it. This will update the account with new card info. Go to Settings> device and/or Registration and de-register from there. Then re-register it from the same menu. That should fix it.
If you have any difficulty on following the steps above, please let me know and I will continue to help you
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