Well I have had this problem before and there are two different things that might be happening.
The first thing is that the hard drive on that Starmail might be going out. The Starmail systems start doing that kind of stuff when the hard drive is on it's way out.
The second thing is that there is a hidden parameter in those Starmail's that is for sensitivity or something like that. Only tech support can get in there and change it though. You would have to call them then transfer them into the voicemail and they set the level.
Those are the only two things that I can suggest that I have run into. If you need a new hard drive I can get you one, I have plenty of them. Give me a call. 210-651-5977. Let me know how it works out.
------------------
www.A1Bizcom.com Specializing in selling and installing new and used Samsung systems