The EFF sent a sister of businessman Johann Rupert packing when offered a meeting that would "benefit" them, the party's leader Julius Malema said at their gala dinner on Friday night.
"The spokesperson of the EFF said 'Can you please tell the Ruperts that at least there must be one party in South Africa which they do not control'," said Malema, seen wearing a black tie and tux in a video posted on the party's Twitter feed.
"And let that party be the EFF. Because the likelihood is that the Ruperts have got everyone except the EFF," said Malema, amid frequent questions over the source of the party's funding.
"We run the risk of all parties in South Africa being owned by the likes of Rupert who have the money to by everything that moves in this country."
Ironicially, journalist Carien du Plessis spotted a bottle of Rupert and Rothschilds's wine on the table at the dinner held on the eve of the party's manifesto launch in Soshanguve on Saturday.
The company's website said it was a partnership between the Rupert family and Baron Benjamin de Rothschild.
Malema told guests at the elegant event that South Africa's problem was not just corruption, but incompetence.
"There are a lot of people who don't steal anything, they are just incompetent," he said.
"There are days where gogo goes to look for her grant and she doesn't find it. Somebody decides they have got more important things to do."
From companies that ignore paying invoices, to a standby doctor who is two hours away from the hospital if there is an emergency - the incompetence is hurting people, he added.
"If we continue with that culture, then we are no different from the type of administration we seek to replace."
Malema said people must not just accept incompetence, and, pulling no punches, he called on black people to be professional and deliver quality because to do otherwise would be punishing the rest of the people.
He said if black people are incompetent, the narrative is "we tried some black here and then it couldn't work".
"You must deliver. As colleagues you must start talking to each other. Everything touched by black must be proper and professional to prove the people wrong because their gospel is we are not capable of everything.
"So how you treat others, particularly your black race, it is because of how you see yourself.
"We are victims of your own self hate," said Malema.
Malema also mooted the idea of offering police officers incentives if their work led to convictions, so they are not tempted by criminals when they are demotivated and having their own financial difficulties.
"If the investigating officer investigates a case so beautifully that the bastard get sent to jail for many years, there must be a bonus."
He was also horrified at the code words Bosasa COO Angelo Agrizzi said were used for some National Prosecuting Authority (NPA) officials - "snake" for Nomcobo Jiba and "snail" for Lawrence Mrwebi.
READ: EXCLUSIVE: Agrizzi to implicate Zuma, Jiba in Bosasa scandal
"You allow literally fat white males to call a beautiful African woman with brains a snake because you have surrendered your soul to white racists.
"We ought to zoom in there and liberate our sisters and brothers at the NPA."
He also suggested criminalising school bunking so that children would stay in school, and implored parents to not send their children to a school with a pit toilet.
"Sending a child to a pit toilet, you are sending them to die. Before you send them into that yard, make sure it is conducive to children."
The party would also discuss its LGBTQI policy when it meets on Saturday.
Watch the speech posted on the party's Twitter feed: