This is an instance where you need to join iMore. You stated, "thanks for the response..." What response? Your previous message, wherever it is, is not joined together with this one so none of us know what was discussed in your previous thread. Having said that, I'm going to start from scratch. What kind of messages are you referring to? Email, iMessage, SMS, MMS, Facebook or what? I do not know why they are "disappearing". Maybe you are deleting them or someone who has access to your device is deleting them.