In WHMCS, there is an option to configure whether credit card details are removed from the system when they expire. By default, WHMCS will remove expired credit card details for security reasons. However, you can adjust this setting if you prefer to retain them.

Here's how you can configure WHMCS to not remove credit card details on expiry:

1. Log into WHMCS: Access your WHMCS admin panel using your username and password.

2. Navigate to Configuration: Click on the "Configuration" tab in the top navigation menu.

3. Automation Settings: Under the "System Settings" section, click on "Automation Settings."

4. Credit Card Storage Options: In the "Automation Settings" section, scroll down to find the option labeled "Credit Card Storage Options."

5. Keep Expired Credit Cards: Check the box that says "Keep expired credit card details on file."

   By checking this option, you instruct WHMCS to retain credit card details even after they have expired.

6. Save Changes: After enabling this option, click the "Save Changes" button to apply your modifications.

Please note that keeping expired credit card details on file may have security and compliance implications, so it's important to carefully consider the risks and consult any applicable legal or regulatory guidelines. Additionally, make sure to inform your clients about your policy regarding the storage of expired credit card details for transparency and trust-building purposes.