I have switched to Nextiva. When Vocalocity switched to Vonage Business I was hoping for better service and call quality. It went downhill. They switched me from servers in Virginia to servers in Portland Oregon, much further distance. The call routing with the low cost vendors they use became a larger failure. I could not call to numbers in our NJ, PA & DE markets and had to email customer service on a daily basis with the problems.
It took months to find a hosted VoIP vendor that could provide service required as we operate as multiple companies from the same office.
After switching to Nextiva our call quality jumped drastically. Calls are now crystal clear and we haven't had many issues with loss of service or call routing.
I would strongly advise that you bypass Vonage Business and contact Nextiva.