United signed 16-year-old David Petrucci from the Giallorossi in July 2008.
“Our coach at the time, Luciano Spalletti, called Sir Alex Ferguson when he got wind of the Petrucci move and asked him to put a stop to it,” Conti said in The Mail on Sunday.
“Ferguson said he would see what he could do. But we heard nothing.
“United are still behaving in this way. It is not sport and it is no way for Sir Alex Ferguson, one of the game’s great leaders, to conduct himself.
“We invest a lot in these young players in time, education and money. The law still allows them to do that but Uefa president Michel Platini is already in talks with the Italian FA to look at ways to eliminate this.”