I've just tried the same thing and am having the same problem. However, I do receive and send txt msgs just fine. Just every time I make a call it hangs up while trying to dial. I too tried soft and hard resets.
Anyone have an idea? The tech support was clueless when I called 611.
I suggest you go to the HP - Palm web site and to the community forums there. You will see a thread how Syniverse, a subsidiary of Altel, ATT, Verizon, et. al changed their coding schemes and that the Palm Treo 700WX can't accomodate the new scheme. I contacted the CEO of Verizon Wireless and they fixed it for me only.