First things first....which ROM are you using?
Are you using Arcsoft v5 something
I am guessing that the registry tweaks have already been done, a soft reset should not affect those nor should a soft reset affect your settings...
Check this first...chances are a pointer got misdirected...
Settings->connections->advanced
You should come up with a couple of things that are called cricket...you can check the settings and make sure that the dial number is #777......Cricket is what it looks for to connect (I oopsed mine and had it as "My connection" and it would not work...it HAS to be cricket)
If that doesnt fix your woes there is a very good thread over at ppcgeeks
Code
http://forum.ppcgeeks.com/showthread.php?t=61034
One thing that you might find is that in your EPST settings it will haveyour username set to something like "yourphonenumber"@vzw3g.com
Follow it and you should be fine...I have a post in there reference the re-authentication...make sure that you change your settings back to re-authenticate...
If that still doesnt work, we will figure it out....the settings for a mogul/xv-6800 can be a little testy....
HTH