I sent an SMS to multiple contacts (30). Signal was weak, I think I had to click try again. iMessage was turned on but obviously all contacts won't have an iphone. Some of the contacts received the SMS (as they replied) but some others confirmed they didn't get the SMS (after I spoke to them as they didnt reply). Now bizarrely some of those who didn't receive the SMS from me (maybe all but I can't be sure) instead received a reply message from one of my contacts who sent it to me (he has an iphone and uses iMessage) How is this possible? How can some people who don't know or have the number of one of my contacts receive messages from him? Why didn't all the original contacts receive the SMS? If it was due to a weak signal then shouldn't I have been notified that some didn't receive the SMS?