South Korea’s telecom authority is fining Facebook 396 million won (approximately $369,705) for slowing down user internet connections in 2016 and 2017.

The Korea Communications Commission (KCC) began investigating Facebook last May and found that the company had illegally limited user access, as reported by ABC News. Local South Korean laws prohibit internet services from rerouting users’ connections to networks in Hong Kong and US instead of local ISPs without notifying those users. In a few cases, such rerouting slowed down users’ connections by as much as 4.5 times. There were 14.5 million Facebook users in South Korea last year and the number is expected to rise to 14.84 million this year, according to Statista.

In a few cases, users’ connections were 4.5 times slower

“Facebook did not actively look into the complaints from local telecoms service providers that users are complaining about slower connections and, as a result, its service quality was not maintained at an appropriate level,” KCC said in a statement, adding that Facebook restored connections last autumn after its rerouting methods became public knowledge in South Korea.

Users would complain to local ISPs about slow connections to Facebook and Instagram several times a day, ABC News noted. For instance, SK Broadband, an ISP that provides home services, received 10 complaints a day, and another ISP, LG UPlus, got 34 complaints a day on average.

“We are disappointed with the KCC’s decision,” Facebook responded in a statement. “We strive to deliver optimal performance for all our users and will continue working with Korean internet service providers toward this goal.” The social media giant argued that its terms of service don’t guarantee that its services won’t be delayed, so it shouldn’t be violating South Korean law. The KCC has not accepted that argument and told Facebook to amend its terms of service.

The case is unrelated to the Cambridge Analytica data mishandling that came to light late last week.