I really doubt it is the Vonage service actually calling you.
What you see is the CID that says what service they're using,(its used to circumvente the laws requiring a CID, its usually either a telemarketer as in my case (cruise trip), or a collection agency.
Some states have laws that will punished "spoofers" such as the calls made to me.
I suggest you contact your state attorney generals office and relate what you seen, and heard, and see what they need you to do to register a complaint.
Some complaints result in fines and even awards to the complainant.
Good luck to you.
I just got one from this number, yet again. I've tried answering before, and telling them to remove my number from their call list. But then some other dumbass calls down the road from the number. I'd change my number if I though it'd do any good... but it wouldn't. I even get mail from Vonage, tryna get me to sign up with them. Apparently they don't get it when ya tell them that you woulda signed with them to begin with if you wanted their service.