As I still have no traction on resolving my Viatalk troubles, I've decided to move my service back to Vonage. I've called up Vonage to reactivate my account. It's been quite a smooth process, though quite a long one. It's taken about 30-45 minutes, but they're on the phone with me to make sure my device works and is hooked up.
So this ended up taking over an hour, all in all a pretty positive experience and inspiring of confidence. I'm not really sure that the process should take an hour, but c'est la vie.