No voicemail symbol

The voicemail symbol has never been active on my FP2. Can anyone help? I get a text message when I have an answerphone message, but no symbol. I then have to dial separately, i.e. I can’t connect directly to voicemail.

I don’t use voicemail, but maybe you can find an answer in the following posts, even if they’re about different problems:

I still haven’t found a way to solve this. Despite having had multiple voicemail messages left in the past month, a notification symbol has never yet appeared. Is this normal? Can anyone from the forum help?