Notes/Domino 4 and 5 Forum

I want to have notes db which can store all the phone calls or voice message into Notes db. My client have alot of mainframe testing at IBM site a year and 100 if users are assigned to come to the IBM site for a the test. Hour before arriving to the site they call to confirm of their present for the test and leave a message on voice message. I want create a db application or use mail db to retreive those voice message or mobile messages so, my client can track who is attending and who is not attending. This is very important feature to have. Do you know any product that i can use. I was aware of one product few years ago but i can't recall it.
Any quick suggestion would be appreciated.
ap