I have the strangest issue. My friend has an iphone and I can text her but she cannot text me back. I have an android phone and t-mobile service and she has AT&T. I have checked my settings and all looks good but I don't think it's my phone since I can text her. I've asked numerous people and noone seems to know why this is happening. I did ask her if she was using imessage and she is not. She said she can text other people who have android phones without a problem...If anyone has a suggestion it would be greatly appreciated.