I want to scream

I have a fairly basic Crackberry (TM) through my job. During my last business trip it became apparent that the CB was screwed up - it would ring but when answered no one was there. I could still make outgoing calls. When I got home I forgot about the problem because I don't get calls on the CB very often unless I'm travelling. Then I was off one day and I got several calls where no one was there. I tried to call back and couldn't (I ended up using my mother's cell phone.) I called Cingular (now the NEW AT&T....arrgghhh, their hold system is SO annoying) and they sent me a new phone after determining they couldn't fix the old one. This was yesterday. The new phone has turned itself off and locked up twice. New phone, round 2.