Some of my texts disappeared - why?
I've got a Nokia Lumia 520; I've been exchanging texts with someone for a few months. I don't know what kind of phone they have. I went to send a text to her and all of our texts from the last few months are gone, except for the last one I sent to her yesterday. Mine AND hers are gone. None of my other texts are missing; everything is intact. I sent her another message and immediately got a "Delivery Failure" response. I sent a message to other number that I know she uses, and she immediately responded with the FIRST number. I'm very confused as to what would cause only some texts from just one person to be gone. Can someone clue me in? Thanks.