Fazeli had represented the Germany international since his 17th birthday and brokered his moves from Schalke to Werder Bremen and then to Real Madrid.
"I have always been either involved in the important decisions on Mesut's future or I was the one who called the shots. I have always been the most important person next to him," Fazeli was quoted as saying by Bild.
"This really hurts on a personal level. His father wants to take care of Mesut's business by himself and we have to accept that. This doesn't affect the friendship between Mesut and me and I wish him all the best."
Although Mustafa Ozil does not yet have the required papers to operate as an agent, Fifa regulations permit him to be the Madrid star's representative because of their kinship.