I've had problems seeing my messages for a little while! It's weird, it would tell me a I had a message and I could tell there was one bc it said that the person wrote me like 45 mins ago or something for example, and yet I can only see the messages I last sent.
I've not tried messages since as it seems they're really temperamental atm D:
@DreamingKoreaBallad - to take a screenshot do a print screen as the easiest way and then just crop it.. you can upload it as a pic then and send it through the email :)