Atletico Madrid have submitted an official complaint concerning the deal when the Blaugrana announced Antoine Griezmann's signing after activating his release clause.
The €120million (£108million) switch was announced on July 12, but Atletico claim that the deal has been sealed before July 1, the day on which the attacker's release clause dropped from €200million to €120million.
Atletico demands an additional €80million (£72million) from Barcelona and to secure the money, the team addressed the issue to La Liga. According to La Liga president Javier Tebas in an interview with Onda Cero, it is possible to cancel a player's transfer
"La Liga will have to decide what course of action to take," Tebas said. "There's a process that has been put in motion and those overseeing it will have to come to resolve the case."
Griezmann debuted for Barcelona on July 23 in a 2-1 pre-season defeat to Chelsea.
The Guardian reports that Barca first approached Griezmann last year, aware that his buyout clause would drop temporarily to €100m. The team was prepared to pay that amount, unilaterally releasing him from his contract, eventually reaching a deal on personal terms.
It left Griezmann's future in his own hands and him deliberating on that matter was featured in a documentary called La Decisión where in carefully styled shots, the player can be seen agonizing over the decision whether to stay or leave.
Griezmann can be heard saying "I don't know what to do" in the film, which was released on June 14. He then comes up with a decision to stay with Atleti and calls Barcelona to offer his apologies. Their board had no idea there was even a documentary despite the production belonging in part to the team's center-half, Gerard Pique.
Griezmann stayed for another season and for some reason regretted renewing. He eventually decided that he did want to leave and so the deal was picked up again for €20m more.
If Atletico's allegations are true, it means that Griezmann had agreed to join Barcelona in the days following Atletico's defeat vs. Juventus in the last 16. There are disagreements now, but the deal has been done. Now La Liga have to decide whether Griezmann will have to stay with his new club or go back.
On May 14, a phone-recorded video was released with Griezmann saying that he was leaving, but at the time he claims he had not reached a decision where to yet. He said he could not tell, but if you Atletico, they said they already knew.
