iPhone 4 no sound resolve

Today make a call to SingTel helpdesk at 1626, they did a reset remotely and manage to resolve speaker no sound issue....

If I know, I will not restore to factory default. Now all my application data are gone.... :( As I did a clear install without application data.

The helpdesk mention it is a software issue. If this happen again, I can try to do a reset under iPhone Settings => General => Reset => Reset Network Settings.

Just cross my finger, don't wish it happen again.