The Ray Charles organization is suing seven of the singer’s children, who are currently attempting to gain copyright control of most of the late singers songs.

According to the court cases, Charles had given each child $500,000 in 2002 with the understanding that they would never seek inheritance claims on his musical estate. The Ray Charles Foundation, which provides funding for research into hearing impairment and educational programs, currently has control over all of the rights to the intellectual property of Charles, who passed away in 2002. The foundation, however, claims that Charles’ children are now violating their agreement by requesting copyrights for more than 50 songs.

“In complete disregard of the confidence, trust, and belief in his own children that their father reposed in them,” the lawsuit says, “by undertaking the actions described below in this Complaint, Defendants’ have reneged on and are in breach or other violation of this agreement.”

According to the suit filed in Central California last week, the children in question appeared in March of 2010 to retrieve the copyrights of the songs, under a provision of the 1976 Copyright Act that is intentionally set to allow artists to renegotiate their royalty rates after a certain number of years if their work vales have appreciated.

The foundation claims that, along with their previous agreement not to seek any further share of their father’s estate, the “termination of transfer” rule does not apply in this circumstance, because Charles had already renegotiated his royalty rates when he met with his publishers in 1980. It also challenges the idea that some of the songs were works for hire, stating that the artist cannot claim the same rights.

The Ray Charles Foundation argues that it would be exceptionally hard hit by the loss of those royalties because it is not allowed to solicit or accept any private donations for their cause.