Agent Jorge Mendes' Gestifute firm has vehemently denied accusations of "blackmail" made by Sporting CP president Bruno de Carvalho over a proposed move for Rui Patricio.
The goalkeeper has been linked with a switch to Napoli or Championship winners Wolves, and the Portugal international has asked to cancel his Sporting contract, according to a report by Record.
Patricio is said to want to leave Sporting following an attack on the club's training ground by supporters this month, after the team missed out on Champions League qualification.
The goalkeeper is reportedly also unhappy with De Carvalho's leadership, having seen coach Jorge Jesus had been fired in the build-up to the Taca de Portugal final, which Sporting surprisingly lost 2-1 to Desportivo das Aves.
De Carvalho suggested Mendes has forced through a move for Patricio, and demanded a cut of the deal and €4million from the transfer of Adrien Silva to Leicester City in January.
Patricio's Sporting future appears in great doubt, but De Carvalho hit out at Mendes and Gestifute over their conduct regarding the deal, although the agency has denied all wrongdoing and instead laid the blame at the door of the Primeira Liga side.
"I want to tell you that Sporting were negotiating with Jorge Mendes, who said that there was a proposal from Napoli, but in the meantime the change of coach at the club [Carlo Ancelotti replacing Maurizio Sarri] ended up cooling that interest, then appeared Wolves," De Carvalho told the media.
"Jorge Mendes' right-hand man called us at 11 at night and asked what was Sporting's position. Of the €18m, Jorge Mendes wanted €7m and we said no. Jorge Mendes wanted to take advantage of the situation, which is a crime.
"When we did the renewals of Adrien [Silva] and Rui, we finished the old contracts and made new ones, the old ones, made by Godinho Lopes, said that both the player and Jorge Mendes had a percentage of the registration. With the new contracts, the percentages of the company Gestifute are annulled.
"Gestifute told us that they wanted €3million from Rui Patricio's business and another €4million from Adrien or we had no business.
De Carvalho has denied Jesus was sacked, while in a statement released on the Gestifute website, Mendes' company hit back at the Sporting CP president over his allegations and said the club had tried to set up a move for Patricio.
"At the press conference held today, regarding the termination of the contract with just cause by player Rui Patricio, the president of Sporting SP accused Gestifute of "blackmail" ('pay us more than €7m or no deal')," the firm said in a lengthy rebuttal. "Nothing is further from the truth.
"Sporting, through executive director Dr Guilherme Pinheiro and its internal lawyer, on May 23, strongly urged Gestifute to try to get a proposal for the transfer of player Rui Patricio, in order to avoid pending his request to intervene, to resolve the dispute with Gestifute concerning player Adrien Silva, without prejudice to the payment of the consideration due to Gestifute, already contractualised by the transfer of player Rui Patricio himself.
"This dispute is related to the intervention of Gestifute in the renewal of the contract of the player Adrien Silva, which also took place at the request of Sporting in 2012, in a situation in which the same Sporting ran the risk of the player being free similarity, incidentally, of what happened at the same time as Rui Patricio himself.
"In return for those services, Gestifute did not immediately charge any amount and its remuneration depended on a future transfer consisting of a percentage of the respective price, which was not duly paid when transferring Adrien Silva to Leicester.
"Nothing in this process - strictly nothing - came about on the initiative of Gestifute."
Gestifute accused Sporting CP of raising the price demanded for Patricio after the player held a medical with the English club - widely reported to be Wolves, who have signed a number of Mendes' clients including manager Nuno Espirito Santo and star midfielder Ruben Neves.
"Gestifute did everything to get the agreement of an English club for the transfer of player Rui Patricio for the €18m euros intended by Sporting, and even the player, satisfied with this possibility, performed medical tests, with authorisation of Sporting," the agency continued. "All this, once again, with the knowledge and express agreement of the president of Sporting.
"Surprisingly, the deal would end up failing late afternoon when Sporting executive manager Dr Guilherme Pinheiro, visibly embarrassed, told Gestifute that the president of Sporting finally demanded an increase in the price of €2m: "two million more or no business" - which was immediately rejected by the buying club. In two words: the business did not fail by any blackmail from Gestifute; the business failed due to an unanticipated and last-minute additional requirement to the already perfectly defined and agreed conditions.
"All of these facts may be confirmed by the said executive director, Dr Guilherme Pinheiro, and an internal lawyer, assuming that his obligation not to be absent from the truth does not overlap with any other dislocated duty of loyalty to those who definitely do not deserve it."
