Why is my visa bank card being declined as a card for payment

Not all debit cards are accepted.

See the Apple Support article below.

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. Either use the form or scroll to the bottom of the page in the 2nd link. Follow through the screens to get a chat or telephone option.  

iTunes Support

iTunes Support – world wide