After received a voicemail, the voicemail notification is always there, even reboot device, even removed the voicemail sms from SIM.
According to spec 23.040, 9.2.3.24.2 Special SMS Message Indication
If the received voicemail has the setting SetIndicationActive=1, then EFmwis(spec 31.102, 4.2.63) should be set. That should be the reason we see voicemail notification whenever insert the SIM.
As EFmwis READ/UPDATE need PIN, another way to remove it is to send another voicemail message from simulator, which has SetIndicationActive=0
