Still no word from them, they used to be relatively quick, but not lately. I’ll keep trying, but I'm making sure updates reach everyone via email, especially those who bought it early on, everyone will get their files regardless, so no worries!
Viewing post in Clover Valley: 16×16 Farming RPG Asset Pack comments
I don't know if generated keys are compatible with items of variable price, but maybe that'd be a solution that would work for giving people access to the items through itch.io? (Understand if you don't want to figure the mess out, though, with a support request waiting.)
It honestly hasn't felt like itch.io care much about its users since it came out the Vintage Story dev hadn't been paid their sales in half a year.