The 28-year-old is currently in his native Brazil, having seemingly refused to return to the UK for training following Conte's decision to drop him from the first-team picture.
Costa previously claimed that he was informed of Conte's decision by text message in June - a notion the club have branded "nonsense" - and is now preparing legal action against his side for the current situation.
"In January, things happened with the coach. I was on the brink of renewing my contract and they put the brakes on it," Costa said in an exclusive interview for the Daily Mail. "I suspect the manager was behind it. He asked for that to happen.
"His ideas are very fixed and clear. I have seen the sort of person he is. He has his own opinion and that will not change. I respect him as a great coach. He has done a good job and I can see that, but as a person, no. He is not a coach who is very close with his players. He is very distant. He doesn't possess charisma.
"He arrived from an Italian league where everyone is very serious and arrived in a dressing room where there are maybe more jokes.
"The worst bit of all this, it is for the fans. They have always treated me so well, always, always. For this, I am sad. I hope they understand things happen in football. Conte is a great coach. He deserves to be where he is but it's his opinion. He has his reasons."
The Blues got their Premier League title defence off to the worst possible start on Saturday as they suffered a shock 3-2 loss to Burnley at Stamford Bridge.