OK the very first thing to try is to go into Phone settings->Services tab and look for the Mode of Operation setting. It should be on Hybrid. If not, try moving it there. If it is on there, try moving it to 1x only and see if that fixes the problem.
Otherwise--here is how to proceed. Flash it with the most current stock Verizon ROM (I assume it's Verizon since you mentioned xv). Here is a link:
http://www.utstarcom.com/pcd/downloa...0_WWE_Ship.exe
Flash that to the phone, and then let it customize your device when it first boots. After it's done, then dial the *228 or whatever you Verizon people dial to provision the phone.
If it still doesn't work then I think you need to approach the seller about a refund.