KT, one of South Korea’s top three telecom carriers, said Wednesday it has found 24 subscribers to its most expensive internet plan, which guarantees a connection of 10 gigabits per second, were not getting the high-speed connection they were paying for.

“Our investigation has found that an error has occurred in our customer data during the process of expanding and upgrading network facilities,” the firm said in a statement posted on its website, offering an apology and compensation.

“We will reexamine and improve our system to automatically detect such failures in service,” it said.

The issue was first raised Saturday by a famous YouTuber who once modeled for KT and has since caught the attention of the Korea Communications Commission.

On Tuesday, the Korea Communications Commission, the country’s telecommunications regulator, pledged a “thorough response” to the issue.

“If KT intentionally made a serious error and provided (internet speeds) to customers different from terms of service, we will launch an investigation and impose restrictions,” a KCC official said.

On Wednesday, the Science, ICT, Broadcasting, and Communications Committee of the National Assembly said it would hold a meeting Thursday and order the KCC and the Ministry of Science and ICT to look into the issue.

ITSub, a YouTuber with 1.7 million subscribers who specializes in IT gadgets and cars, claimed that he found that KT had been limiting the internet upload and download speeds of his studio to 100 megabits per second, which was 100 times slower than 10 gigabit-per-second plan he was on.

According to the video, ITSub had dialed KT’s customer service center to protest and requested the issue not to be repeated. However, the YouTuber received an answer that it’s up to customers to check and prove slowdowns of internet speeds. After contacting the customer service center, ITSub’s internet speed problem was resolved in 30 minutes, which sparked a greater controversy whether KT had intentionally limited the internet speeds.

On Monday, KT released an official statement that the case was a misunderstanding triggered by a system error. KT argues that when ITSub recently moved to a new studio, his information wasn’t properly updated, and 100 Mbps internet was provided instead of 10 Gbps. In response to ITSub allegations, KT unlisted its 10 Gbps internet commercial in which ITSub appeared as a model.

By Kim Byung-wook (kbw@heraldcorp.com)