Samsung Galaxy S3 — Messages ordered in an odd fashion

Hi,

So recently my message function has been playing up. In the notification bar, the new message would be there once you click it and go to the message thread, it would either disappear or be placed further back. Ive googled and most people say that its to do with date and time, ive set it back to automatic date and time and automatic time zone, though the problem is still there.

So Ive talked to samsung but they just say reset my phone, and i just dont want to lose messages, apps, contacts and all of that.
I have backed up most stuff with Samsung Kies but I just dont think its very reliable.

Is there anything I can do to rearrange my texts?
Im running 4.1.2, and i understand there is 4.2.2. How do i update it? If i can update it?

What am i able to do to fix this other than deleting everything?
Are there any programs I can use to backup my messages too?

Thanks, hopefully someone can provide an answer