NEW MEMBER - ??? About UNLOCKED RZR??

[$uperstang]

So I just purchased a new unlocked razr for my wife, put her sim card in it and it works for like 3 hours fine. Then she tries to call out and keeps getting error "call failed" non stop no matter signal strength. So I go in to the network settings and I set it to T-mobile and register, pretty cool since this is my first time playing with this stuff. I tell her now it has to be fine. Well it was for about a day and then started acting up again. So I call T-mobile and ask for help, they were great by the way! I was told to go in to settings for network and set the type to MANUAL, then select Cingular The number read 310-410 and register it? I did and it seems to be working fine using Cingular's network for a few days now with no problems? Does this seem right? Well If I shut it off it deverts back to it's standard settings and I have to manualy change it every time, which is ok with me as long as it works considering I hardly ever turn it off anyway. But my wife works in a hospital and has to turn it off all the time, how do I change this?