I hope you're trolling.
You could not earn a ton of gralats from the old upload system. Spending 20,000 gralats in period A, and refunding for 10,000 gralats in period B is not an earning. It is a loss. This is not a bug or an exploit, it is actually not in the best interest of players to do this, as over time they have lost 10,000 gralats. The developers simply noticed a phenomenon whereby players tend to refund old uploads that they don't use for a quick gralat increase. But this is not unfair or an exploit because again, they are actually losing gralats over time. So, developers realized this and decided to stop players from doing it in order to force them to buy gralat packs instead if they want a quick increase in gralats for an event or something.