Cingular having trouble with voicemail

Both my wife and I picked up Cingular Razr phones several months ago and for the most part have been very happy with them. The phone itself is wonderfully designed, it’s rugged, fits in your pocket, and is just easy to use. However, the little details can often matter so much.
Both of us have been having increasing trouble with the voicemail on our phone. The voicemail itself works fine, while the commands are somewhat counterintuitive. The problem lies with the phones ability to sync with the voicemail service. For about a week my phone would keep telling me that I had voicemail. I would check, but there would be no new messages. No matter what I did I couldn’t get the phone to recognize that I had deleted all of the messages. I rebooted it, took the battery out, did everything I could think of to get it to resync with the system. Then one day it finally did clear out.
This last week it’s gone the other way. Everything was working fine except my wife asked why I didn’t respond to a message she had left. A day after she had left the message the phone still hadn’t noticed that I had a voicemail. When I did call the voicemail system I was surprised to find that I had 4 messages waiting with no notifications on the phone.
My wife has been having the same issues with her phone and lack of notifications and it’s not that we’re out of service area, we’re both driving all over the SF Bay Area during the day with the phones on. There just seems to be an issue with the phones ability to sync with the voicemail service. This is a problem though in that you can no longer trust your phone.
Update: 1/25
So, it appears that the problem was on the phone side. There’s an option to turn off notifications for voicemail in the menu of the Message Center. After working for some time on tracking the problem down with a coworker, we found this option had been switched off. Not sure how that happened, but things are working now.