can the c7100v be used with optimum internet and voice

> Is this compatible with optimum internet and voice [...]

   I have no idea.

> [...] also even i was not able to reach the admin page connection was
> refused..

   You should not need an Internet connection to get to the web
interface on these things.  "not able" is not a useful problem
description.  It does not say what you did.  It does not say what
happened when you did it.  As usual, showing actual actions with their
actual results (error messages, ...) can be more helpful than vague
descriptions or interpretations.

   Depending on exactly what you tried to do, a "connection refused"
message might mean that you reached the device, but there was no such
server running there.  For example, using "https://<whatever>" might
fail that way, while "http://<whatever>" might work.