Thank you for your concerns. Due to the ongoing developments between itch and its payment processors we can no longer sell Isekai RPG on itch. We can't even offer the (optional) paid upgrades without triggering itch's deindexing.
Until itch's policy changes we can only collect payment through Patreon. Any previous version you've bought through itch should still be available. If you have any issues accessing what you've paid for please let us know.