cannot update my credit card information

See Change, add, or remove Apple ID payment methods https://support.apple.com/en-us/HT201266--in The App and iTunes Stores.

But, if you want to change on your device,

On an iPhone use Settings > Name > Payment & Shipping

For a Mac, see Set up your Apple ID payment method and shipping address on Mac https://support.apple.com/guide/mac-help/set-apple-payment-method-shipping-address-mac-mchl29cac995/mac

What happens when you try? Error message(s)?

Log into your account in the App Store/iTunes and you should be able to change/verify it there. Or you can click the blue Edit payment methods in the article below. When signed in and the page loads, you will be on the credit card page. After updating that, click the Go Back button at the lower left and you will be on the address page.

Apple ID payment information - change.  

If necessary, contact iTunes Support for assistance. See the Apple Support articles below for contact information.   

iTunes Support – world wide 

Apple Support schedule phone call       

If necessary, try Twitter

https://twitter.com/AppleSupport.          People have posted it may take an hour or more to get a response.