I tried to add my new card and it just keeps saying failed

Reasons your payment card may be declined 

Account suspended for suspected fraud. 

Address in your iTunes account does not match exactly the billing address for the card 

Error in credit card number 

Insufficient balance or you still owe money on a subscription 

The card was not issued in the country of the iTunes store 

Wrong expiration date 

Wrong security (CVV) code 

You are connected through a VPN provider that makes iTunes think you live elsewhere - uninstall VPN 

You live  in India About billing for Apple subscriptions and media products in India – Apple Support (UK) 

You live in Russian Federation or use Russian banks or cards 

Here is additional information from Apple if your payment method is declined. 

If your payment method is declined in the App Store or iTunes Store - Apple Support