On May 30, Mobile & Apps reported that Blizzard was being investigated over its refunds policy regarding Diablo 3. The World of Warcraft developer refused Korean players refunds as the product had been used, but The Korea Fair Trade Commission said Korean law allowed products to be returned within seven days as long as the issue prompting the refunds was not consumer-caused.

The Korea Times said the Fair Trade Commission suspects the company of having "violated the country's laws on electronic commerce and commercial contracts." The FTC added it raided Blizzard's Seoul office Monday, May 28, and secured "related documents and other evidence" to determine if Blizzard broke Korean law.

The issue is one of many Blizzard has experienced since releasing Diablo 3 May 15. The game debuted with server and log-in errors, followed by reports of stolen accounts and cross-country disputes between Korean and Chinese players after the latter group obtained illegal copies of the game and played on Korean servers. Diablo 3 is currently not available in China.

The game has sold 6.3 million copies according to the latest official figures, selling 3.5 million copies in 24 hours following launch.

The FTC said Blizzard's refund refusal was "disadvantageous" to customers.

On the server issues, Blizzard said the server capacity has been doubled and added on the official Diablo 3 forums issues are continually being monitored. Servers went offline for an hour Thursday, May 31, for fixes, rumored to be linked with the reported exploits.

Despite the issues, the game is currently sold out on Amazon.co.uk, but not in the U.S. Copies of the regular edition will arrive June 8, 2012 for the former.

"We have received many complaints from Diablo 3 users," Kim Hyung-bae - a spokesperson for the FTC - said.

FTC officials also said the investigation is to determine if Diablo 3 was sold unfairly, so consumers could not claim for refunds. It added Blizzard is being investigated for "ill-preparation" for the volume of traffic experienced during launch. The Korea Teams claimed some investigators expect the FTC to order Blizzard to issue refunds to all unhappy customers.