SK Telecom, the nation’s largest telecom operator, promised massive compensation Friday for its service failure a day earlier.

Its chief executive officer Ha Sung-min apologized for the technical glitch that affected calling and text messaging for an estimated 5.6 million customers in Seoul and some provincial areas.

“I apologize to shareholders and customers for yesterday’s incident. We will compensate for the damages with more money than stated in the customer clauses,” Ha said after a shareholders’ meeting.

The subscribers had trouble making calls or using data services such as email and map and navigation applications for six hours in Seoul and regions in the southwestern part of Korea, including Gwangju City and South Jeolla Province.

SK Telecom held a press event the same day, saying that “the number of affected customers is expected to be 5.6 million. We will compensate them monetarily with 10 times the phone charges, more than the six times stated in customer clauses.”

Under SK Telecom’s customer clauses, if a network failure lasts for over three hours in one day or over six hours in a month and users are not at fault, they can be compensated with six times the phone charges for the duration of the glitch.

“The government will keep an eye on whether SK Telecom takes appropriate compensation measures,” said Ko Chang-hyu, an official at the Ministry of Science, ICT and Future Planning’s telecommunications infrastructure policy division.

SK Telecom said the problem was mainly caused by technical glitches in home location registration systems, which find callers’ locations. As the equipment broke down, it was not able to find callers’ base stations.

The company posted an apology on its website at 11 p.m., six hours after the start of the incident.

“We apologize to affected customers for any inconveniences caused by the service failures, and the modules were restored in 24 minutes,” SK Telecom said.

However the problem lingered until midnight, and the company’s foot-dragging response came under fire.

Due to the delayed response, the company’s website was bombarded with user complaints and inquiries, causing the site to crash temporally. Some taxi drivers who use SK Telecom’s network for their payment systems had trouble receiving payments. The association of drivers is now moving to file a class action suit, an industry source said.

This incident has surprised many users as it came only a week after the company had a mobile Internet disconnection due to a problem with its long-term evolution and 3G network equipment last Thursday.

For 20 minutes, subscribers experienced difficulty connecting to the Internet and were not able to use messaging services. Last week, the company said the problem was caused by a malfunction of outside equipment that was connected to its wireless network.

By Shin Ji-hye (shinjh@heraldcorp.com)