According to reports the REAL reason Floyd Mayweather stopped dealing with 50 Cent is because 50 tried to take advantage of Floyd while he was locked up...
From Fight Hype
When news about the formation of The Money Team [TMT] Promotions first broke back in July, we were led to believe that the company was created as a joint business venture between [Floyd Mayweather and 50 Cent].
However, FightHype.com has discovered that was not the case at all. What was once described as a "breath of fresh air" actually turned out to be an attempted coup by those once considered to be close to Mayweather.
Apparently, as [50 Cent and former Mayweather associate Tommy Summers ] spoke to fighters, they painted a picture that Mayweather was indeed on board, when in reality, he wasn't. The notion that Mayweather was involved is one of the reasons why IBF featherweight champion Billy Dib was quick to sign with TMT Promotions, only to later find out that the facts were misrepresented to him. There was also an attempt to move former WBA featherweight champion Celestino Caballero to TMT Promotions, despite the fact that he was already signed with Mayweather Promotions.
Sources have informed us that 50 Cent and Tommy Summers tried to take advantage of Mayweather's incarceration in an attempt to oust long-time adviser Al Haymon in hopes of gaining control of Mayweather's career, both in and out of the ring. With the help of the influential Haymon, Mayweather has built a brand that has made him the highest-paid athlete in all sports. Their working relationship has allowed him to shatter pay-per-view records and generate revenue like no other fighter has ever seen before. One would think that Mayweather's achievements speak volumes about his working relationship with Haymon and their ability to succeed. Apparently, 50 Cent and Tommy Summers didn't see it that way. Ultimately, greed may have been the single solitary factor that caused long-time friends to go their separate ways.