There is no other storefront just buy your game and join the discord there you go you've secured your game now fight about it in the discord instead of here.
Both of them do not accept any of my visa/mastercard card nor debit and other payment options are not availeble. I would say crypto but that is impossible for the shitty sites you mention especially subscribestar.
i know subscribestar works but subscribestar also happens to check your browsing history somehow and block people that have visited piracy sites it appears as the site declining your card. only fix is making a new subscribestar account and using a different credit card on a fresh browser
I think what's more likely is that they do the same thing that fantia does: if it's an image, they will insert some fingerprint data through steganography to trace which account leaks what image. Once their scrapers detect one, it flags the account that's connected to that identifier.
Subscribestar is trustworthy but it will just refuse to process if you have visited like kimono or some other subscription site scraper theres a specific type of cookie that it uses to do that which other websites like google and facebook use to track users even after a cookie wipe
