Why can I not use the credit card I’ve been using all along. I’ m getting a message saying I tunes can not except this form of payment

Start here, see -> Payment methods you can use with your Apple ID

Payment methods you can use with your Apple ID – Apple Support (UK)

fyi: Not all credit & debit cards seem to work with App Store / iTunes Store, try a different one, or preferably a credit card. If your card is not accepted as a paymenf method, you need to contact your bank.

See also: iCloud+ plans and pricing

iCloud+ plans and pricing - Apple Support

• Accepted payment methods for iCloud+ upgrades include credit cards, debit cards, and your Apple Account balance. If you don't have enough available funds in your Apple Account balance to complete your upgrade, you'll be charged the remaining amount. Apple Store gift cards aren't accepted as payment for upgrading iCloud+. Learn how to manage the amount of storage you're using.