http://www.elmundo.es/deportes/futbol/2017/06/17/59442c74e5fdea8a5c8b4677.html (sorry, in spanish)
It's a good article about what happened. Mendes has created a complex of screen companies that already begins to affect him. Firstly with Falcao, also on trial (
http://www.elmundo.es/deportes/football-leaks/2017/06/14/59411543468aeb320a8b458a.html ), as he points him out as the responsible adviser in tax fraud offenses.
Mendes in the same time appointed to Madrid, to pay the fine with a new contract.
Madrid are willing to support to a certain extent but they don´t want to repeat the role of Barcelona with Messi and will not allow public blackmail. (The article says that the renewal of Messi is stopped because he tries to add the total of the fine)
"Futbolistically" I think it would be a mistake to leave now, in the best moment of Madrid in decades. To say that in Spain he´s treated like a criminal is a mistake. If he wants to go, it would be a great business for Madrid. I thought he´d leave in June 2018 but it would be reasonable to sell now for more than what we paid after 8 years.
Madrid don´t retain players against their will.