Voicemail - Who called me?

[Andym2]

If I'm in a flakey signal area and someone calls me, it goes straight to voicemail without registering a missed call.

I get a text stating you have a new message (no number shown)

Then when the caller leaves a message without reading out their phone number I cannot call them back as the voicemail system does not tell me the number of the caller.

This cant be right can it?

When I'm in a good signal area, not only does the number appear as a missed call, I get a text stating I have a new message from xxxxxxxxxx

I used to be with BT business mobile and the numbers were available for returning calls.

Have I missed something?

[Blossomland]

@Andym2  Did you resolve this and find out how to retrieve the caller's number? 

[Andym2]

No, never found a solution. Still happens when in certain areas. I can get a text from voicemail a couple of days later saying I have missed a call and the caller did not leave a message yet I do not have a missed call registered.