I would agree with christcorp, if you have it disconnected from the telco, it could be grounded some where that could fry it by the voltage difference from the grounds. Also if that wasn't a problem the length of wire running around the house can act like an antenna and cause problems too.

Your best bet would be to not use the Voipo's device and get your own ATA then you can do what you want and not damage the Voipo's device.