my iphone declined the debit card

Were there any other indications when the payment method was declined?

According to Reference Article above, a wider and general view, covers most.

"..If you can't make purchases or update your apps, including free apps,

there might be a problem with your payment method. To fix this, add a

new payment method or update your payment information.."

While there also may be other contributing factors in that occurrence, it may

be a good idea to spell-out the exact happening; and/or what you've tried..

And there are several steps; places to check your device or other accounts.

A different means of payment may need to be used; or tried instead of debit,

in case there's an issue with some specific bank, etc.

Not sure what else to say, as you've given little else to go on.

As a fellow Apple product user, and volunteer in these ASC

discussions, most of us have some ideas. ~ Some, with better

ideas & experiences, in their off-time; or I've come to think so.