Panic attacked?

Nope, not me.
But it's my iPhone4, to be exact.
It is obviously in a shock of receiving many calls and messages and emails pushed in, since I'm back at work this week.
Today, it has completely went bezerk..

The ringer and speaker phone works.

But it turns mute to alarm/ alerts, keyboard clicks and videos.

And I cant hear the caller talking, unless with the loud speaker, or the earphone.

Well, I've googled and it seems that this is kinda common issues.

This is among the majority cases reported regarding iPhone.

Anyway, I've tried all of the suggested method here, but the result is still deafening.

So, what now?

Hmm.. pass me the smartphones catalog, please?

(pic googled from the net)