I'm living in Switzerland and here the upper-left icon is not used to inform us about voice messages (we receive a SMS instead).
The problem is: when I was "playing" with smart messaging, I sent a missformed message that enabled the upper-left icon.
If I can enable this icon via SMS, for sure I can disable it ;-) Where can I find the relevant information. In fact, this icon is not annoying, but if I'm able to enable and disable it through SMS, I can easily use it for an other purpose.
Thanks in advance!