Tatu's management claimed Julia Volkova (right) was ill
Organisers of the two UK Tatu concerts cancelled on Wednesday are suing the pop act's management over having to pull the dates.
The show's promoters, EEM Group, said on Wednesday the Russian pop act's managers had put "unachievable and numerous obstacles" in the way of the shows, and that they were suing them for £300,000.
The concerts, due to take place at the London Wembley Arena on Friday and the Manchester MEN Arena on Sunday, were cancelled due to poor ticket sales.
Promoter Andy Talakin said his company was given no idea of the content of the show, and if there was going to be any immoral content.
The teenage pop stars have drawn some complaints because of lesbian imagery and dressing in school uniforms in the video for their debut single, All the Things She Said.
Mr Talakin said Tatu's management had asked for 300 under-16 girls dressed in school uniforms for each of the gigs.
"We feel that such an exploitation of the image of underage children is morally totally unacceptable," he said.
He said the final straw was when management had said one of the duo, 17-year-old Julia Volkova, would be unable to sing because of illness, but that management would "persuade" her to sing if they were paid more.
A publicist for the tour had said there had been no evidence of Volkova's illness.
Volkova and Lena Katina, 18, became the first Russian act to have a UK number one with All the Things She Said earlier this year
Both venues for their shows have capacities of more than 10,000, and the concerts were understood to have sold only a fraction of available tickets.
A spokesman for the duo's label Interscope said on Wednesday that Tatu had still flown into the country for promotion of a new single, Not Gonna Get Us, which is out this month.
The pair have only one public appearance planned, at a central London record shop on Tuesday.