The U.S. Federal Trade Commission filed a complaint against T-Mobile USA on Tuesday, alleging that the wireless provider added millions of dollars of unauthorized charges onto customers bills, a practice known as cramming. The charges were for subscriptions for services like horoscopes or celebrity gossip, which often cost $9.99 a month. T-Mobile USA received 35 to 40 percent of the amount charged, the FTC said in its complaint. The FTC also alleged that T-Mobile USA was refunding to up 40 percent of some of the charges in a given month, which the agency said should have been a signal to the wireless company that the charges were fraudulent. T-Mobile USA did not immediately respond to requests for comment.