I have been following the interview too. I think the problem should be about money, he's indirectly claiming that some of Ferre's vocals are his so it is likely that Ferre never paid him anything. He's also sang some of Ferre's young brother and his namesake Guy Digital's vocals on Boite Noire and he confirms that he gave those vocals to his cousin Guy.
If you listen carefully, he says he's not as successful as Ferre and he doesn't sing better than Ferre but he's better than Ferre because Ferre buys his songs whilst he Guy composes his songs.
He's also shot down Kabose Bulembi whom he says is a fake singer who Werrason kicked out and his music is not played anywhere,even saying Fabrice and Robinho are doing better because their music is playing in the popular night clubs in Kinshasa but not Kabose's music.
This guy is simply bitter or he's using the same strategy that everyone else uses to attract attention, polemic!!!