I don't have the answer.
But I did look at their website, and first impression is they are not at all user friendly. For example, to even see a FAQ page, they want you to fill out your name, email and other contact info, then they evidently get back to you. Looks the same for any support pages. They look much more like b-to-b (business to business) than residential focused. You can't even tell with any certanity from their website if they are BYOD -- bring your own device, such as an Obi.
Contrast that with other providers, like CallCentric,
Voip.ms, Anveo and others who have illustrated instructions or tutorials readily available on their websites, who directly answer questions on various forums (dslr), and it's a telling signal why not too many people on here mention using Alcazar. I'm just saying.