The Brazil international had agreed a move to Cruzeiro from Vasco da Gama, but the Brazilian National Treasury have blocked the move until Vasco have cleared their unpaid Treasury debt.
The Dede deal allowed Vasco to use the £4.8m fee to pay back a portion of their debts, but the transfer has been blocked indefinitely until the government department is satisfied that the club has fully paid off its remaining obligations.
Still, Dede is desperate to seal the move to Cruzeiro, and his agent confirmed the player has filed a legal challenge to force through the deal.
"We have already filed a lawsuit, we took all the measures and we are waiting for our lawyer's response."
But until the Treasury have received their dues, they will continue to block the transfer, as Rubens Lopes, the president of the Rio de Janeiro FA, revealed.
He told Radio Brasil: "There is a judicial decision preventing Dede from moving to any other club. If Vasco owe money, no person should be prevented from working because of someone else's debts.
"I think Vasco can solve this situation."
Dede has eight caps for Brazil, and was linked with a move to Europe earlier this season.
Manchester United and Liverpool were both thought to be interested in the defender, with Sir Alex Ferguson believed to be keen to bring him to Old Trafford this summer.