"Alfredo Di Stefano has lost his freedom," said Gina Gonzalez, a Costa Rican who has worked as the Argentine ex-player's secretary, in a statement she read out to reporters in Madrid.
"I have absolutely credible information that in recent days Alfredo has picked up the telephone in his home and contacted certain people and that at that moment the call has been cut off, because they have taken the telephone from him to stop him talking," she said.
"It is clear that his freedom is being snatched away from him."
Di Stefano is one of Real Madrid's most celebrated players, having represented the club for 11 seasons between 1953 and 1964, winning five European Cups. He now holds the title of honorary club president.
He announced in an interview in El Mundo newspaper on May 4th that he planned to marry Gonzalez.
"I am in love and I am getting married to Gina," the newspaper quoted him as saying. "I want to and I have been a widower for eight years."
His children have applied for him to be placed under legal guardianship on the grounds of ill health.
That move "is based exclusively on our desire to obtain his maximum protection in all aspects of his life", the family said in a statement, adding that he had been examined by a psychiatrist.
Gonzalez said she had gone to the police about the matter but that nothing appeared to have come of her complaint.
She called on the Spanish Football Federation, the European and world football bodies UEFA and FIFA and even the Argentine government to intervene.
El Pais newspaper said Di Stefano was not a particularly rich man but that the right to the use of his name in sports-related publicity after his death would be very lucrative.