A week has passed since first emailing subscribestar support and they still have not replied to me. Here is an update based on what I can gather.
The main page cannot be publicly accessed. But this link seems to work: https://subscribestar.adult/baraag/subscribe
Only previous subscribers can renew/extend their support. Any new patrons attempting to subscribe will have their card declined.
With substar’s support for baraag becoming seemingly deprecated for future subscribers, I will test alternatives.