DIS representative Roberto Moreno claims the Catalan club will be hit with a fresh legal dispute in South America and says the company still want 40 per cent of the fee
The 21-year-old's move from Santos to Barca last summer is already being investigated in Spain and led to the resignation of Blaugrana president Sandro Rosell last week.
But the deal is also causing a stir in Brazil, with Santos now saying they will take the player's father to court over the €40 million (£32.8m) payment revealed by Barcelona, in addition to the €17.1m (£14m) fee paid to the club, and the Catalan club now look set to face further legal action from third-party owners DIS, who claim they were not paid their share.
"DIS presented a judicial lawsuit against Barcelona, Neymar, Santos and [agent] Wagner Ribeiro," lawyer Roberto Moreno told Catalan station La Xarxa on Friday. "It has been presented in Brazil and now it will be presented to the justice system in Spain."
Moreno also questioned Rosell's resignation and claimed the supermarket chain will continue to fight for the 40 per cent of the fee they say they are still owed.
"If there was no problem with Sandro Rosell, why did he resign? It's very strange," he said.
And he added: "We want that 40% from the Neymar operation. We feel very cheated by Neymar's father and by Neymar - very cheated and very sad.
"We had a lot of affection for his father and we helped both Neymar and his family. Real Madrid's offer was much better than Barca's, but DIS was never called to any of the negotiations with Madrid or Barca. They did it all behind our backs."