Performing rights organization BMI has filed a lawsuit in the U.S. Federal Court against mobile carrier T-Mobile USA for allegedly selling ringback tones without acquiring the proper licenses. A report in the Register says the lawsuit was filed on December 19. “Despite extensive BMI efforts spanning several years, T-Mobile has not signed a license agreement,” BMI said in a statement to The Register.

Performing rights organizations receive royalties when their artists songs are performed publicly. But different parties may have a different definition of a public performance. For example, in a summary judgment in an ASCAP lawsuit against Verizon, a federal court stated in a summary judgment that neither ringtones played in public nor a mobile carrier’s distribution of a ringtone constitute public performances.