By Marina Lopes WASHINGTON (Reuters) – T-Mobile US added 552,000 postpaid customers in August, more customer additions than any other month in the history of the company, Chief Executive John Legere told investors at a conference in New York on Friday. The fourth largest U.S. wireless carrier also added 208,000 pre-paid customers in August. Valuable postpaid customers pay for their service after usage, while pre-paid customers pay in advance. The company has turned around years of subscriber losses through aggressive promotions in the past year and a half. …
