We were promised several features, which our engineer documented and designed for us, and were never delivered these. When we asked, we were told we'd need to pay thousands more. When we inquired about Salesforce integration, we were told that no matter what we wanted to do we'd need to pay $3,000. Conversely, when we switched to Fonality, Salesforce integration was free.
The staff had no idea how to help us repeatedly, the system is extremely unintuitive, requires logging in to three different places, etc.
But fundamentally, we were promised a whole host of things that were never delivered. The person assigned to us to support us was no capable of helping with technical questions, and when we asked for what we'd been promised and showed documentation of those promises we were told we'd need to pay more than was in the contract or that we could not have them. Finally, when we decided to leave the company, they would not even let us leave our contract early despite the documentation we had of their broken promises.
I would strongly recommend you go with the much more customer-friendly, elegant solutions like Fonality than this first generation, clunky, unintuitive VOIP company.