Hello, sorry I think I had initially misunderstood how the pricing worked on itch.io and should have set the price on the project as a whole, but I had set it on the actual file - so that now there's a new file available, it's trying to charge you again, which was not my intention.
I have now set the price on the entire project, and reverted it back to $1 because I assume you won't be the only person with this problem. I hope you can now get the latest file without having to pay again?