One of my subscribers reported that a pre-paid Paygoo card worked after his other cards were rejected. You can also try contacting the SubscribeStar support team.
Unfortunately, paygoo seems to only be available in physical stores in norway and Scandinavia. I've already tried signing up to revolut's prepaid cards too but to no avail.
I've tried contacting support but I'm not hopeful.
I've already given up. I guess it just isn't in my destiny. I'll wait until public release next month.