Please refer to the this EnV VX9900 Troubleshooting Guide for any help you may need.
Identification and Background
The Lg EnV was the follow up to The V. The EnV is smaller (4.5" long, 2" wide, and .75" thick) than it predecessor and also came in a variety of colors. It was followed by the EnV 2 which was smaller and had a bigger screen (compared the EnV's 1.75" screen). Other successors were the EnV 3, the LG Voyager, and the EnV Touch.
For further comparing this to the VX9800, please refer to this helpful video by CNET here.
Information specs such as general, cellular, messaging, internet, and communications information and more are also available here.