Why I can’t mark Apple ID use with credit cards?

Change, add or remove Apple ID payment methods

https://support.apple.com/en-us/HT201266

ASC - Late 2012 Mac mini, macOS 10.14.6; Watch, series 5 GPS/cellular, watchOS 6.2; iPad Air 2, ipadOS 13.5.1; iPhone 8+, iOS 13.5.1; TV 4th Gen, tvOS 13.4.6;  HomePods, audioOS 13.4.6 and Airport Express w/ Airplay 2

Payment method declined?

Apple ID payment information - If your payment method is declined, or you have a billing issue with a previous purchase in the iTunes Store. 

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.