@Dubstar_04, unfortunately the bug makes the phone store some information on the SIM that need your intervention to get reset. This should clear the flag:
1. Power off the phone / set flight mode
2. Leave a voicemail message using another phone
3. Power on the phone / unset flight mode
4. Listen and remove your pending voicemail from your ubuntu phone
After 4 you should receive some information from the network that will remove the voicemail message.
@Dubstar_04, unfortunately the bug makes the phone store some information on the SIM that need your intervention to get reset. This should clear the flag:
1. Power off the phone / set flight mode
2. Leave a voicemail message using another phone
3. Power on the phone / unset flight mode
4. Listen and remove your pending voicemail from your ubuntu phone
After 4 you should receive some information from the network that will remove the voicemail message.