Dreams about communication breaking down usually point to anxiety about being heard or reaching someone who matters. The phone dying specifically suggests a fear that something important won't get across, or that you'll lose your chance to connect right when it counts. Since you're feeling panic and helplessness in the dream, it's probably tapping into real-life stress about a relationship, conversation, or situation where you feel like the outcome is slipping out of your control.
The fact that it happens right before they pick up is the key detail here. It's not about the call never happening - it's about being SO CLOSE but failing at the last second. That's the kind of dream detail that usually reflects something in your waking life where you're worried about messing up when it matters most, or where communication feels fragile. Could be about work, could be about someone personal, could be about something you've been trying to say but haven't quite managed yet.
The pattern of having it twice in a month suggests this is something on your mind lately, not just a random dream. Pay attention to what's actually stressing you about communication or connection right now. Sometimes just identifying what the dream is reflecting on - and maybe addressing it directly - makes the dream stop repeating. Your brain's basically trying to tell you something isn't sitting right.