How can I fix...

I just got the BlackBerry Pearl 8130 about 2 weeks ago and I'm getting a little frustrated. When I first got it, it deleted all my text messages and call log after I looked at it. I played around with it a bit and it stop deleting stuff, but now it's doing it again but it's not even showing me I have messages or missed calls and I can't see who called either. My messages and call log is completely empty all the time...even when I make calls, it isn't showing up. It's really starting to get frustrating, because unless I have my phone on me at all times, I'm missing messages and calls. Is there anything I can do to fix this? Thanks.