I have an iPhone 5 using the mobile app, with AT&T carrier, and no desktop type phone, just the mobile. I usually have my iPhone on silent with the buzz on. When a RingCentral call comes in, it just gives one little buzz and that's it. I need it to ring/buzz like my AT&T calls such that it rings multiple times, else I miss the call. I've been told by support that it is behaving like any application that gives a notification. It should behave like a phone call, which is what other providers do. This is a bit of a showstopper for me, as it means I miss most of my calls.