Hello I received a message from a person this morning and we where chatting, my text were in a blue bubble and hers in a gray bubble. We finalized the conversation and after an hour I sent her a text, from there my text are in a green bubble and has written "Sent as a text message". Why the change in colors and the message? I haven't received a reply from this person since. I am on an iPhone iOS 8.3 Thank you.