"Manchester United's treatment of us has been unprofessional and unbecoming," he said. "They've broken the rules and I have reported their approach.
"Considering we are fighting for our lives, their behaviour has been despicable. The relationship between the clubs is at an all-time low.
"We are realistic enough to know that sometimes you can't keep a player and we understand why he would want to go to Old Trafford.
"But they don't want him now, they want him on the cheap when his contract runs out. Why don't they just do this all the time. They could close their Academy."