No longer have credit card that was on this account

I am just not sure what led you to the page to verify your payment information. I previously thought maybe you forgot your Password, but is it that you were attempting to make a purchase and required to verify your payment information or you are finding that your current payment method is no longer valid on your Apple Account?

If that is the case and you no longer have that card, then you would first need to add a new card, then you can delete the old one.

Add a payment method to your Apple Account – Apple Support (UK).

Is it possible it is simply referring to what is usually called a "CVV" which is the 3 digit code on the back of the card?

Security Code?

• Do you mean Security Questions or Apple Account Password?
• Did you forget your Password and are using the iforgot website?

One of the options to gain access to an account without a security delay is by providing the CC info used for account transactions to prove your identity. You may still be able to reset the password without it, but it will likely require a waiting period without sufficient information to prove who you are or without another Trusted Device or Trusted Phone Number set up on your account to be used for that purpose.