SK Broadband said Thursday that it had countersued Netflix for network usage fees based on a June verdict that favored the South Korean company.

The SK Telecom subsidiary, one of the country’s leading broadband internet access providers, said the suit, filed with the Seoul High Court, was a follow-up measure after Netflix failed to respond to SK’s proposals.

“Despite the fact that massive investments are made in maintaining the internet network every year and the fact that it is not a free service, Netflix is still using the company’s network without paying due fees,” SK Broadband said in a statement.

According to the SK firm, data traffic has surged explosively each year, from 50 gigabits per second in May 2018 to 1,200 gigabits per second as of September.

The rapid growth is incurring losses for SK, it said.

Netflix has appealed since losing the case in June. The verdict at the time said, “Netflix is being provided a paid internet connection service through SK Broadband, and it is reasonable and fair that Netflix pays for the service.”

“Denying the need to pay is an act of denying the basic business model of the telecommunications business,” SK said. “As all other content providers pay for the network, Netflix should pay the fees.”