The Minecraft Market back end has received a huge overhaul recently. This caused a few glitches here and there which I've been trying to fix. Apparently I set the daily spending limit to 0.50, which is of course not what we want. It's back to 200 to prevent children from accidentally emptying their parent's bank accounts on the HappyDiggers market while not getting in the way of big spenders. Who knows, maybe one day someone will want to by the Epic rank, twice
Please try again and let me know if you run into any other problems.