LONDON/FRANKFURT (Reuters) – French low-cost telecom operator Iliad has set a mid-October deadline to decide whether to improve its bid for T-Mobile US or walk away as it faces resistance from seller Deutsche Telekom, several people familiar with the situation said. Deutsche Telekom, which owns 66 percent of the fourth-largest U.S. Under the deal structure proposed by Iliad, Deutsche Telekom would have to keep a stake in the combined company. Iliad is currently in talks with several U.S.