Many South Korean players were angered due to massive server crashes and high latency while playing Diablo III. The Wall Street Journal reports that 66% of Diablo III online traffic in Asia comes from the country.
As for the refund itself, there are a few stipulations. It currently extends to players who haven't reached level 40. If eligible, the customer has to file for a refund between June 25th and July 3rd. Past that date, Blizzard said that it will offer refunds for any players under level 20 within 14 days of their purchasing the game. The studio is also extending an olive branch to upset gamers by handing out 30-day trials to StarCraft II.