If I call somebody and their phone is dead should I get a ringtone?

I'm usually not the insecure type but the girl I'm dating says her phone went dead which is believable. I called her back and it rang and I kept calling to be a lil annoying not knowing the phone was supposly dead almost 20 minutes goes by and she calls back and said her phone was dead I told her that it didn't cause it didn't go straight to voicemail. This has happen before but i just don't believe her. She has a iphone 6 with straight talk. I just want a answer I have always thought since a kid if it goes straight to voicemail then its dead or off

It's possible. I think that it depends on the phone carrier (eg. Optus, Telstra, vodafone.) :)

Yes usually when the phone battery drains out n phone shuts off any calls will go straight to voicemail cause there's no where else for it to go. But as the other user mentioned it depends on carrier you have, but usually it goes to voicemail. But if it has no service on the phone it will tell you the phone is no longer in service