Issues changing payment method for iCloud

It’s a billing problem for use of iCloud. New credit card company assigned me new card # and Apple won’t accept my payment.

My payment credit card I pay with monthly with auto withdrawal is now owned by a new company. They gave me a new account number, but only the last four digits. This won’t allow me to change my method of payment to you. What can I do?

[Re-Titled by Moderator]