The list of high-profile people that Apple Music, Apple’s paid streaming service, has angered is growing—Taylor Swift? Check. US Senator Al Franken? Check.

Franken aired his concerns in a letter addressed to the Justice Department and the Federal Trade Commission on Wednesday. In the letter, Franken urged the DoJ and the FTC to investigate Apple for engaging in anticompetitive activity.

According to the senator, Apple is abusing its position as a giant player in the device and music platform market to push its own products and undercut its competitors. For example, Apple charges a 30 percent fee for purchases made in third party apps—like Spotify—but exempts Apple Music from that fee.