Nikita Mazepin has confirmed that he is proceeding with legal action against Haas.
The Russian driver, and his father's company Uralkali that was the American Formula 1 team's title sponsor at the time, were instantly expelled from the paddock early this year amid the wave of western sanctions over the Ukraine conflict.
Mazepin, who subsequently set up a fund to support other Russian athletes affected by the sanctions, revealed to Russian journalists that he is suing Haas.
"When the contract was terminated, Haas was in arrears in wages to me," he is quoted by Championat. "They still haven't paid it.
"It seems to me that the employer should at least compensate for the salary until the moment of dismissal and, probably, pay some kind of severance pay," Mazepin added.
"And when the whole world is kicking you, it's probably wrong. But that is just my opinion.
"What I'm talking about is that contractual obligations were not fulfilled," he insisted.
Mazepin said that whether his father Dmitry also sues Haas over the terminated title sponsorship deal is a separate matter.
"You need to understand that we had two independent contracts," he explained. "And breaking the agreement with the title sponsor did not have a direct impact on my future in the team.
"So the team made two separate decisions. As I didn't see my money, we are going to court. This is my personal story."
Mazepin says the paperwork has "already been filed with the court".
