Payment declined when trying to upgrade iCould storage

I’m trying to get more iCloud storage but the payment keeps getting declined. Each time I’ve tried i get the following message “Check your payment information and try again”

My payment information is fine (it’s the same card I always use, hasn’t expired or anything) and the issue seems to be with the storage only, because I was able to purchase some books successfully (and things outside of apple too).

There are no authorisations or anything showing up on my bank. Anyone know what’s going on and what can I do to fix it?