By Diane Bartz WASHINGTON (Reuters) – U.S. authorities filed a complaint against T-Mobile USA on Tuesday, accusing the wireless provider of adding 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 delivered by text message, which often cost $9.99 a month. T-Mobile USA received 35 to 40 percent of the amount charged, the Federal Trade Commission (FTC) said. The Federal Communications Commission also announced it was investigating T-Mobile USA for cramming and said it would coordinate with the FTC. The FTC asked the court to order T-Mobile USA, the fourth-largest U.S. mobile phone provider by number of customers, to stop mobile cramming, provide refunds and give up any revenues from the practice.