I have a new 5c from T-Moble with a puzzling problem. One of my contacts on Sprint can't get through. When he calls the voice message says he is blocked at the owner's request. I have not blocked anyone. I added him to my Favorites list and re-did the contacts card for him. He has the iPhone 4 and can receive a message from me and I can get a message from him but no voice calls. The first message he sends are blue but repeated ones have grey backgrounds. T-Moble phone support checked its settings and said all were OK. At the T-Moble store we did a restore on the phone without success so a replacement is on order. I am not convinced that the problem is with the iPhone or any settings I have made to the phone. Has anyone encountered this type of problem?