There's no such thing as a Verizon 9800.
Use the Enterprise Readiness tool in BESC to check to see if the data plan is provisioned properly. https://besc.webapps.blackberry.com/besc/dashboard/
You edited the device.xml file manually? That's a bad move.
What version of BES are you using?
There's many reasons why an activation would fail. Can you provide more details?
Have you gone through the Enterprise Activation Troubleshooting KB article yet?