Hi naz68,
We understand that your iCloud storage payment is being declined for some reason, and we'd like to help. When you view your billing information for the iTunes and App Stores, does the address match what your card issuer has on file? Are your Apple ID region and the billing address region the same? If so, are you able to add a different card or payment method? This will help us better determine where the problem is happening.
Here's how to add an alternate card or change the payment method:
Change, add, or remove Apple ID payment methods
Please let us know what you find.
Take care.