I think I may have find a solution ot my problem.
So just to recap the original issue:
- I got my ST SIM card just 3 days ago
- Voicemail testing was done in my office
- With the ST SIM card in my Galaxy Note, keypad "1" is pre-programmed to dial +16192040806
- Whether I call the number directly OR press and hold keypad "1", the only message I got is "Goodbye" and the call ended
Just yesterday, I drove for lunch, which is about 1 mile away from my office and I try to call the VM again and this time it works. I can setup my VM, enter my password, etc. Tried to call again and I got into my VM successfully.
Back to my office, I press and hold "1" again, but this time, instead of connecting directly to my VM, I got a message "Please enter your mailbox".
So it looks like, in my office, I am connecting to a cell tower that, SOMEHOW, screw up my VM. But if I am connecting to another tower, it works just fine.
I will test this theory by downloading an app called Open Signal, which show which tower I am connecting to at a certain location.