My iPhone doesn’t accept my credit card

Try this -> Sign in to your Apple ID account page and edit / update your Apple ID details.

https://appleid.apple.com

On the Sidebar click Payment methods -> then tap Payments Methods and tap Manage payment method.

Or -> Change, add or remove Apple ID payment methods

Change, add or remove Apple ID payment methods – Apple Support (UK)

Call Apple in your region see: Contact Apple for support and service

Contact Apple for support and service - Apple Support

Contact Apple Support -> Get Support (apple.com)