NHK is suing the head of a minor opposition party critical of the broadcaster, arguing that he has not paid his subscription fees.

NHK filed the lawsuit Monday with the Tokyo District Court demanding that Takashi Tachibana, 52, pay two months of subscription fees totaling ¥4,560.

After winning a seat in the Upper House through the proportional representation system, he visited NHK in August and set up a subscription with the broadcaster for a TV in his office in the building for members of the Upper House. He refused to pay and insisted at the time that the issue would be hashed out in court.

Yet Tachibana, who established the political group NHK Kara Kokumin o Mamoru To (Party to Protect the People from NHK), had to relinquish the office space when he ran, unsuccessfully, for a seat in an Upper House by-election in Saitama Prefecture on Sunday.

To enter the election, Tachibana, a former employee of NHK, vacated his Diet seat, which is now held by another member of his party.

Tachibana’s party seeks to abolish the current mandatory payment of subscription fees to NHK and scramble the broadcaster’s programs so that only viewers who pay fees would be able to see them.

The Supreme Court ruled in 2017 that owners of televisions are legally required to sign up with NHK and pay subscription fees, dismissing a claim that the mandatory system violates the freedom of contract guaranteed by the Constitution.

NHK usually does not disclose individual contracts or lawsuits, but the broadcaster said it decided to make the case public after receiving “many calls (from its viewers) to take stringent action” against Tachibana.