I bought a Jio sim card four months ago and as we cannot call through our Diller via Jio sim card they asked me to download Jio 4G voice I can call with this app but really speaking this app in not at all user friendly it takes a lot of time to search contacts and not only that but also some times the call gets disconnected automatically and not only that sometimes I have to wait for a long time to call as this app can only call when Jio 4 G voice is online and many a times it is offline so this is very frustrating when I am in a hurry to call someone actually this app is not so user-friendly and I am not at all satisfied with it but we have no option if we have to call via Jio sim then we have to use this app as a here is no other option