PPCGeeks - Assistance needed after clearing phone

So my HTC Titan XV6800 for Verizon had been acting fine since I acquired it and was using it. A couple of days ago all of a sudden it started freezing and acting crazy for no reason, and I could never keep it to stay on for anything. I kept having to take the battery out or hard resetting it, and when I would turn it back on the battery would be drained horribly. So I cleared the phone completely because it seemed like removing programs wasn't even helping. When I cleared the phone not only did I clear it the phone is now back to how it was before it was unlocked to Page Plus which is under Verizon.

I need to know how to unlock my phone and set it back up under my provider seeming as how I'm still under service with them. I have all the #s from out of the device's information, I just need to know how to get it back to Verizon so that it can be used with Page Plus.

Thanks.