Doesnt work with iPhone (unless phone is using WiFi)

Installed this on my Mac desktop so that I could Facetime with my family who have iPhones. Problem is, that the person with the iPhone cannot connect from just anywhere! They have to be using WiFi, *not their phone plan connection*, if that makes any sense. For instance, when my son is a passenger in a car, or walking down the street he cannot receive/send Facetime, but he CAN when he is at home (with WiFi), or at the library, which has free WiFi. Glad that it was only .99, but I am very sorry that I wasted a dollar.

Openminded One about FaceTime, v1.0.2