Hello
With thanks to @Decoyaudio, please find the steps below to remove the Network Provider Voicemail notification when stuck.
You need to dial 901 and switch your notification method to SMS then switch it back again. The step by step insructions can be seen below ↘️
- Dial 901
- Press *
- Press 5
- Press 1
- Hang up
- Dial 901 again
- Press *
Press 5
- Press 3
- Hang up
Good luck 😁