By default, credit card numbers are masked by NetSuite. You'll will need to open a ticket with NS Support asking to have the ability to have the view full credit card number permission added. They will ask you to sign some paperwork acknowledging that you're taking on the responsibility for maintaining PCI compliance on your own.
From the NetSuite help file:
Important: To see unmasked credit card numbers, a user must log in using a role with View Unencrypted Credit Cards permission. Before you can grant View Unencrypted Credit Card permission, an administrator must contact NetSuite Customer Support and provide a signed agreement. NetSuite Customer Support then activates the View Unencrypted Credit Cards permission for your account.