I have just been through a 4 month challenge with my phone manufacture/service provider. I bought a new phone. I decided prior to my purchase I wanted some thing that would fit my business needs. I decided on the Treo 750. The concept is great. The content is unbelievable and I enjoy using it until I got a call one day and I was asked ,don't you return phone calls? With out my knowledge I had not been getting voice mail notification. My voice mail box was full. After returning all of the calls I started to work on figuring out why the system was not working. I contacted the service provider which is also the company I bought the phone from and we began on a 4 month journey that finally ended January 18 2008. I will cut to the chase and say that after 5 replacement phones and the problem still not repaired I was about to give up. I had been requesting a new phone instead of a refurbished one and finally in January I got to talk to a wonderful understanding lady at AT&T. Please no that the entire time I was dealing with this every one I came in contact with at AT&T was wonderful ,professional and wanted to help. This lady at AT&T finally agreed to send me a brand new phone. I was elated. Got the new phone, installed the battery, programed some numbers in and sent my self a voice mail. Nothing, Nothing happen. My first thought was I did some thing wrong. I read the instructions again. I wanted to be sure. I do not remember how it happen but I took the sim card out of my wife's phone and put it in my old Treo and all of a sudden the voice mail notification was working. I could not believe it. I was shocked. No one has brought that possibility up. So I got a new sim card and every is working great!