I have lost track of how many times I have told people: just because you hear a phone ringing on your end, doesn't mean it's ringing on my end. (Verizon US, and yes, you as a caller will hear ringing while my phone sits silent.) Leave a voicemail. It can be short, it can be almost devoid of meaning, but if you send it, I will at least know that you called. If you don't? No record at all. I was out of range, you left nothing to be tracked by...