My sister didn't get a call, she has Verizon, so it might not work for that either.. sucks that you can only send 1 phone call though (to each number that is).
It works on verizon cell phones. I did it to my best friend at work and hes on verizon. Though it didn't work when I sent it to my partners cell (as me and him are on a family plan with verizon) in the bedroom next to me.