'We are informing you that it is impossible for us to send the International Transfer Certificate for Santos player Robinho' CBF general secretary Marco Antonio Teixeira wrote in a fax to the Spanish Football Federation (RFEF).
'Santos will not accept the transfer without full payment of the buy-out clause in the contract which is legally binding under Brazilian law and which is fixed at $50 million.'
Last week nine-times European champions Real deposited a guarantee to pay $30 million to Santos with the CBF which equated to 60 percent of the buy-out clause in order to buy the club's share of Robinho's rights.
The 21-year-old Brazilian international has reportedly waived the 40 percent to which he was entitled.
'It's what we were expecting' Real's head of media and communications Antonio Garcia Ferreras told Reuters from Thailand where the team are on tour.
'But I'm convinced that the deal will go through and that Robinho will definitely be included in the squad when we go to pre-season training in Austria.'
Santos have turned down Real's approaches for the youngster who has a contract until 2008 insisting that the Spanish side pay the buy-out clause in full.
Santos president Marcelo Teixeira has denied there was any verbal agreement between himself and Robinho that would allow the player to leave and criticised the player's refusal to train with the squad.
'Robinho's behaviour since he returned from the Confederations Cup has been has not been ideal' Teixeira told Spanish sports daily AS.
'It surprised me when he refused to turn up to work. He should show more affection towards his team mates.
'What he says doesn't correspond with the truth which is something the player is doing more often now. I never had a verbal agreement with the player that would allow him to leave.
'There is nothing that allows the buy-out clause to be divided. It is 100 percent if the player leaves unilaterally. If it is by mutual agreement it is split 60-40. Robinho has been badly advised.'
Real return from their tour of the United States and Asia on July 30 and leave for their pre-season training camp in Austria at the end of next week.