So per my conversation with Vonage, just a few moments ago - they said if you buy a used device, you can activate it to a new account, but much like a cell phone, if it was on a contract or had money owed, you would be responsible for those expenses if you were to use that device.
So my question becomes - is this device going to be free and clear of any expense ? Did you have a month-to-month plan with them, or did you pay to cancel your contract ?