No Voicemail Visual Notification appears Redmi 7a

[Newbie999]

Hi, I switched phone companies, Ive put in a new 'Sim' everything works fine, but im NOT getting a Visual 'Icon' at top of 'Home' screen , to tell me there is a Voicemail waiting for me .. I used to get a small, '2 circles, with a line through' type icon, .. but i now do NOT get ANY Notification for Voicemail ..I can only check messages, by randomly, dialling my 'Voicemail' number and checking if anyone has left me a Message !! How can i get this 'Voicemail' Notification (Visual ) Icon back , when someone has left me a 'Voicemail' ? Thanks in Advance !
Xiaomi Redmi, 7a , Android 10 ....