Try looking for the link they gave you when you paid, that would allow you to access if I'm not mistaken.
Hey, mate. I am still waiting for them to answer back to see if they can solve the issue. However, I think that the problem is on your end. Because it says that I bought the game but I can't access the paid files. Instead, if I look into other games I have bought, I can download everything. I think that maybe you need to check which files you allow people to download.
Sadly it's not, this is not the only game this has happen on. Eternum recently increased their price and Itch locked out people who bought in at a lower cost. Love and Sex bought that one on sale can't download that one ether until it goes free to everyone. It seems Itch has no means for devs to increase there price nor the ability to handle sales past an initial download. Try to contact Itch to get answers good luck. Stop buying on Itch