As we have stated a couple of pages ago, we are willing to reimburse anyone that had lost coins because of them (will take some investigation, so not everyone message us trying to get free coins)
Wasn't that pool on a different fork on its own? So people were fast mining themselves in that pool hitting blocks at a way faster rate than the rest of the network.. so something like mining 500 coins with 5mhs/s just didn't happen in the correct chain.