So I contacted the data protection officer listed on Square Enix's website, at the recommendation of my local data protection agency, with regards to GDPR 'right to rectification'.
Interestingly they say that 'country/region of registration' is considered a
historical fact, and not subject to rectification.
I've asked for further clarification on what personal data is being used for payment processing, as I don't believe historical fact can be conflated with current billing address.
I've never encountered a payment processor that didn't require a listed country when taking your payment details so if that information is not being pulled from 'country of registration', I wonder where it is being pulled from.
This feels like a bit of a rabbit hole honestly...
