Atletico Madrid's managing director Clemente Villaverde has maintained the club's innocence in reference to the alleged irregularities in signing underage players.
The reigning La Liga champions are currently being investigated for allegedly breaching transfer rules relating to foreign minors, and if found guilty, the club could face a similar ban to that which Barcelona received for the same offence last year.
The Catalan giants were given a two-window sanction after being found guilty of the offence, but Villaverde claims that Atletico "have done everything by the book".
"We've complied fully with every single formality throughout the process. We've told FIFA everything about every single player included in the report and we're sure we have done everything by the book," the managing director said, according to Goal.com.
Real Madrid have been accused of the same offence but have also refuted the claims.