Romelu Lukaku’s agent, Federico Pastorello, says he and his family received threats while he was working on the striker’s £97.5m Chelsea move.
Lukaku, 28, left Inter Milan after helping the club end its 11-year wait for a 19th Italian title.
Pastorello says talk the deal was “engineered” or “forced” for financial gain “is leading everyone astray”.
“Many of those who today insult me and threaten me, thanked me wholeheartedly for bringing him to Milan,” he said.
“I have always accepted – and will continue to do so – confrontation and constructive criticism: they are part of the game for those who play a role with considerable media relevance.
“What we absolutely cannot tolerate are the falsehoods, insinuations, insults and threats we have received [also against my family and my daughters], which have far exceeded the limits of civilisation, decency and tolerance.”
Lukaku scored 64 goals in 95 appearance in his two seasons at the San Siro, helping the Nerazzurri to a first Scudetto since 2010 in his final term.
The move made Belgium’s all-time top goalscorer the most expensive player ever sold by a Serie A side and comes at time that the club are facing financial difficulties.
Despite saying he was happy to stay with the Italian champions, Lukaku reversed his stance earlier this month and told Inter that he wanted to join Chelsea if the right offer was received.
“Believe it or not, the supporters affection and the special bond with the city of Milan made him think about it for a long time: but then, once he made his decision, he carried on with conviction and firmness,” Pastorello said.
“The economic aspect is a detail, but it is not the main factor that determines our choices and those of our clients.
“With regards to FC Internazionale, I can guarantee that the Sport CEO Giuseppe Marotta, the sporting director Piero Ausilio – as well as the coach Simone Inzaghi, who worked at this personally – did everything in their power to avoid this transfer.
“But there are circumstances that go beyond their decision-making range and depend on the instructions of the owners.”