i don't think there's any way to undo that but if you want, please consider gifting a friend a copy or donating for another community copy (:
copying from the summary:
community copies: the minimum purchase price is set to 5 usd, but by paying above the minimum price, you can donate community copies for other users & also support me in making more games like this.
if you buy a copy at 5 usd that will cover the cost of the community copy you claimed but that would just mean you end up with 2 copies i think. however, you can choose to gift a copy to somebody else if you have their email from the purchase screen.