New Mac Apple ID won't accept payment details
Ring them.
Or rather, get them to ring you - which they will, in English, to Spain

Start at https://getsupport.apple.com 

I've had to do a similar thing in the past when setting up my folk's new Mac last year, British accounts, English speakers, Spanish address.

They are incredibly helpful &amp; patient. You really won't regret having bought a Mac.